<Li> Isaiah Washington as Dr. Preston Burke </Li> <Li> Patrick Dempsey as Dr. Derek Shepherd </Li> <Table> <Tr> <Th> No . overall </Th> <Th> No. in season </Th> <Th> Title </Th> <Th> Directed by </Th> <Th> Written by </Th> <Th> Original air date </Th> <Th> U.S. viewers (millions) </Th> </Tr> <Tr> <Th> 37 </Th> <Td> </Td> <Td> "Time Has Come Today" </Td> <Td> Daniel Minahan </Td> <Td> Shonda Rhimes </Td> <Td> September 21, 2006 (2006 - 09 - 21) </Td> <Td> 25.41 </Td> </Tr> <Tr> <Td_colspan="7"> The interns of Seattle Grace Hospital help Izzie cope with the loss of her fiancé, Denny Duquette as well as her decision to quit the internship program . Meredith is uncertain what the future holds after she has sex with Derek and whether he is willing to leave Addison after a marriage of eleven years . Addison finds Meredith's panties in Derek's tux pocket, and realizes that he slept with Meredith . After spending the night in his office, Webber is confronted by his wife, Adele (Loretta Devine). She gives him an ultimatum, forcing him to decide between his career and his marriage . Addison and Alex treat a newborn baby who was found abandoned in a trash can, and they are faced with four minors who could be the mother . George seeks relationship advice from Derek after they are forced to stay under quarantine in the locker room, when Derek confesses his feeling towards Meredith . Bailey gets attached to a patient in isolation whose wife dies, and relives the moments when her husband's life was threatened . </Td> </Tr> <Tr> <Th> 38 </Th> <Td> </Td> <Td> "I Am a Tree" </Td> <Td> Jeff Melman </Td> <Td> Krista Vernoff </Td> <Td> September 28, 2006 (2006 - 09 - 28) </Td> <Td> 23.48 </Td> </Tr> <Tr> <Td_colspan="7"> Cristina makes a bad first impression on Burke's parents and is also surprised to find that he is a "mama's boy". Burke's mother believes that Cristina is too selfish and driven for her son, and is only trying to take advantage of his extensive knowledge of cardiothoracic surgery . Izzie uses baking to cope with her grieving, and bakes hundreds of muffins . After pinning Meredith's panties to a bulletin board, Addison takes a day off from the hospital and spends the day drinking . Due to Addison taking the day off, Bailey has Alex help her in the pit, and they're faced with a teenage patient who has been impaled on a tree branch . A brain tumor patient quizzes Meredith and Cristina over their respective relationships . Webber discovers that Callie has been living in the hospital and tells her she has to leave because of hospital policy . Bailey finds the panties on the bulletin board and loses it, demanding to know who they belong to . Callie sees Meredith's embarrassment and takes the blame, which in turn causes George to become jealous, fearing Callie might have cheated on him . A surgical patient lives what may be her last day to the fullest . Meredith must choose between Derek and Finn, and struggles coming to a decision . In the end she tells them both that she would like to try dating them both instead . </Td> </Tr> <Tr> <Th> 39 </Th> <Td> </Td> <Td> "Sometimes a Fantasy" </Td> <Td> Adam Arkin </Td> <Td> Debora Cahn </Td> <Td> October 5, 2006 (2006 - 10 - 05) </Td> <Td> 22.80 </Td> </Tr> <Tr> <Td_colspan="7"> Cristina is determined to help Burke overcome his hand tremor and get back into the operating room . Izzie attempts to return to the hospital for the first time since she left the program, but ends up standing in front of the hospital all day, unable to go in and confront Webber . Alex treats a young patient who has a long history of injuries, leading him to suspect abuse . It is discovered that she can't feel pain which makes her believe she is a super hero . Derek and Cristina treat a man who elects to have brain surgery so he is able to look after his child . George gets annoyed at Callie after she moves in with him, resulting in them arguing over a patient . Meredith gets annoyed as both Derek and Finn interrupt the other as they are dating her . Mark is determined to get back together with Addison, but she continuously refuses him . </Td> </Tr> <Tr> <Th> 40 </Th> <Td> </Td> <Td> "What I Am" </Td> <Td> Dan Lerner </Td> <Td> Allan Heinberg </Td> <Td> October 12, 2006 (2006 - 10 - 12) </Td> <Td> 22.88 </Td> </Tr> <Tr> <Td_colspan="7"> Meredith's appendix bursts and she is admitted for surgery . Addison works with a pregnant woman who wants to give birth naturally, but needs to have a cesarean section . Addison begins to doubt her abilities as a surgeon after Derek broke up with her; Addison takes Alex off her rotation . Meredith is high from the painkillers and she and Addison speak frankly and apologize to each other . The interns work with a car salesman who wants to get back to his regular routine after he has a risky surgery, however, he lights a cigarette that catches his face on fire . Derek and Mark argue over the best way to treat him, each believing that their specialty is the most important and pressing . Callie breaks things off with George after he stands her up for Izzie, and she later hooks up with Mark . Derek clears Burke for surgery again, but Burke has serious doubts about whether his hand is ready or able to perform surgery again . He keeps his doubts to himself, except to tell Cristina . He practices on a corpse and he and Cristina realize his hand can't perform surgery unless he has help . They decide together to hide the truth by having Cristina assist him in his surgeries . After her surgery, Meredith makes a decision between Derek and Finn, telling Finn that he is a good man and probably a better man, but Derek is "the one". Izzie meets Denny's father, who gives her 8.7 million dollars according to Denny's wishes . </Td> </Tr> <Tr> <Th> 41 </Th> <Td> 5 </Td> <Td> "Oh, the Guilt" </Td> <Td> Jeff Melman </Td> <Td> Zoanne Clack & Tony Phelan & Joan Rater </Td> <Td> October 19, 2006 (2006 - 10 - 19) </Td> <Td> 22.05 </Td> </Tr> <Tr> <Td_colspan="7"> The interns are excited to attend their first Morbidity and Mortality conference but their excitement evaporates quickly after finding out Denny Duquette is first on the agenda . Bailey is raked over the coals for letting her interns run unsupervised about the hospital for long durations. Bailey treats a young mother battling breast cancer and realizes that she blames her infant son for everything that had happened to her . Derek and Addison finalize their divorce; Derek gives up most of their property to Addison but later learns that Mark and Addison's relationship was not just a one - night affair and that they kept seeing each other for three months . Addison and Meredith treat a former couple who got stuck inside one another during sex, however, after separating the pair, the man has a heart attack that causes him go into surgery . In the midst of the surgery, Burke's right hand begins to tremble again . Cristina covers for him by asking to practice her running whipstitch . Izzie decides to give up surgery after receiving Denny's check, but she becomes re-motivated after watching Cristina operate . Callie confesses to Meredith that she slept with another man, but doesn't name Mark . Meredith contemplates telling Derek about her break up with Finn, but is hesitant, despite the fellow interns telling her to let him know as fast as she can . George is surprised when Callie tells him that she broke up with him . </Td> </Tr> <Tr> <Th> 42 </Th> <Td> 6 </Td> <Td> "Let the Angels Commit" </Td> <Td> Jessica Yu </Td> <Td> Stacy McKee </Td> <Td> November 2, 2006 (2006 - 11 - 02) </Td> <Td> 21.02 </Td> </Tr> <Tr> <Td_colspan="7"> Cristina scrubs in on the rare "humpty dumpty" surgery, much to the envy of her fellow doctors . Bailey wants to scrub in and writes her name on the surgical board as the resident in charge . Cristina erases Bailey's name in order to cover for Burke's hand tremor, which leads Bailey to believe that he was the one responsible for the deletion, leading her to question her talent for surgery and becoming discouraged . Derek receives a surprise visit from his sister and learns that she had slept with Mark, something that threatens their fragile friendship . George and Addison work with a pregnant woman with an unusual dilemma . Mark takes Alex off plastics after he chooses Addison's patient over being on hold at the DMV for Mark, but he later witnesses Mark and Callie discussing their one - night stand . Izzie returns to work, but is on probation and is not allowed to talk to patients, perform any surgery, or even go into an operating room . Bailey directs Meredith to be Izzie's boss for the day and the two treat a patient that may need to be admitted into psychiatry . At the end of the episode, Bailey witnesses Cristina reorganizing the operations board, and becomes suspicious . </Td> </Tr> <Tr> <Th> 43 </Th> <Td> 7 </Td> <Td> "Where the Boys Are" </Td> <Td> Daniel Minahan </Td> <Td> Mark Wilding </Td> <Td> November 9, 2006 (2006 - 11 - 09) </Td> <Td> 20.65 </Td> </Tr> <Tr> <Td_colspan="7"> Derek invites Burke to join him on a quiet camping trip, but George, Alex, Webber, Joe and Walter come along, ruining Derek's plans . George notices Burke's hand tremor whilst fishing with him, but Burke brushes off George's concerns . Addison and Callie team up to work on a patient but realize that their passion for medicine is not the only thing they share, as they had both slept with Mark and later regretted it . Alex tells George that Callie slept with Mark, and he is unable to accept the truth, even though he and Callie were broken up at the time . Things go from bad to worse when George and Alex fight, and Walter gets injured in the process . Meredith assists Mark on a sex - change procedure as he keeps trying to get her to sleep with him, but complications arise when it's discovered that the patient has breast cancer . Bailey confronts Cristina after realizing that she was the one to erase Bailey's name off the surgery board, not Burke, and finally regains confidence in her abilities as a surgeon . As a result, Bailey takes revenge on Cristina by assigning her to the case of a child who swallowed 21 Monopoly pieces, and keeps her off surgeries until she admits why she took Bailey's name off the board . Izzie has to have a counselling session with Sydney, the perky resident who annoyed the interns when Bailey was on maternity leave . </Td> </Tr> <Tr> <Th> 44 </Th> <Td> 8 </Td> <Td> "Staring at the Sun" </Td> <Td> Jeff Melman </Td> <Td> Gabrielle Stanton & Harry Werksman, Jr . </Td> <Td> November 16, 2006 (2006 - 11 - 16) </Td> <Td> 20.92 </Td> </Tr> <Tr> <Td_colspan="7"> Harold O'Malley is admitted to Seattle Grace Hospital, and George's brothers come along and become friendly with Callie . George, however, does not want Callie to socialize with his family, so he assures her that their relationship is over, with no chances of reconciliation . Meredith tries to take things slow with Derek and refuses to have sex with him, while he tries to have a civilized relationship with his now ex-wife, Addison . Derek and Addison confront Webber when they believe he may be suffering from depression . Alex and Izzie help Mark treat a man after he received pectoral implants, and following on from advice from the patient, Alex kisses Izzie after he realizes that he still has feelings for her which are not returned . George and Bailey are on the verge of discovering Burke's condition . Meredith and Bailey treat a five - year old girl, who was accidentally run over by her nanny . </Td> </Tr> <Tr> <Th> 45 </Th> <Td> 9 </Td> <Td> "From a Whisper to a Scream" </Td> <Td> Julie Anne Robinson </Td> <Td> Kip Koenig </Td> <Td> November 23, 2006 (2006 - 11 - 23) </Td> <Td> 18.51 </Td> </Tr> <Tr> <Td_colspan="7"> A traumatic car accident which fills the emergency room has everyone challenged emotionally . George calls Erica Hahn from Seattle Presbyterian Hospital to perform heart surgery on his father after he finds out about Burke's condition . George's parents task Izzie with finding out why George had them change surgeon, but this only leads to George snapping at Izzie . Meredith figures out that Burke needs Cristina to operate . Cristina has a crisis of conscience about her deceptive teamwork with Burke, and turns to Webber . Burke is shocked to see that Webber is considering replacing him with Dr. Hahn as the Chief of Cardiothoracic Surgery at Seattle Grace Hospital, but eventually learns that Webber's plan was to make him Chief after his retirement . However, after Cristina confesses about his hand tremor, Webber is forced to warn him about the severe consequences he will have to face . Callie attempts to rebuild her relationship with George . Addison, Mark, and Alex work together on a pregnant woman, and Alex and Addison realize they may have feelings for each other . </Td> </Tr> <Tr> <Th> 46 </Th> <Td> 10 </Td> <Td> "Don't Stand So Close to Me" </Td> <Td> Seith Mann </Td> <Td> Carolina Paiz </Td> <Td> November 30, 2006 (2006 - 11 - 30) </Td> <Td> 24.01 </Td> </Tr> <Tr> <Td_colspan="7"> Recent events strain Burke and Cristina's relationship and they both realize that the chances of reconciliation are lowering . Meredith's half - sister, Molly, goes into labor and is admitted to Seattle Grace Hospital under the care of Addison . Meredith does not want to see or talk to Susan, her stepmother, and tells her that she is not family and their relationship should go no further . Harold attempts to discover the cause of George's anger . Derek and Mark must work together when two conjoined brothers seek medical help for separation . However, the patients could become paralyzed or die following the procedure, and Derek is unsure on whether to continue until he gets a pep talk from Bailey . Webber demands that Burke has surgery again to fix his hand . Meredith has to tell her mother that Webber will not keep seeing her and she relives the night that he left her for good twenty years ago . Meredith is devastated when her mother says that she should never have had a daughter as she believes that is the reason that Webber had left her . Cristina faces the wrath of Bailey and the other interns following her part in Burke's scheme . </Td> </Tr> <Tr> <Th> 47 </Th> <Td> 11 </Td> <Td> "Six Days (Part 1)" </Td> <Td> Greg Yaitanes </Td> <Td> Krista Vernoff </Td> <Td> January 11, 2007 (2007 - 01 - 11) </Td> <Td> 23.03 </Td> </Tr> <Tr> <Td_colspan="7"> After a successful heart surgery performed by Dr. Hahn, George's father undergoes surgery to remove the tumor that has spread through his body . Webber and Bailey perform the surgery and do a certain procedure according to Mr. O'Malley's wishes, in spite of their medical opinion . Thatcher Grey visits Seattle Grace Hospital to stay by the side of his daughter Molly, who has just given birth to a girl . Meredith has trouble connecting to him and hesitates in talking to him all day long . Alex works with Addison when the baby needs an emergency surgery, and afterwards they nearly kiss . Derek has trouble sleeping due to Meredith's disturbing snoring as she learns that he had been sleeping on the couch for days . A young girl is admitted to the hospital, suffering from a severe bone condition that is thought to be inoperable . Despite Derek's neurological advice, Callie believes that a certain expensive surgery might be live - saving . Izzie begs to scrub in on a surgery, but Bailey refuses to let her do so until she cashes in her check . </Td> </Tr> <Tr> <Th> 48 </Th> <Td> 12 </Td> <Td> "Six Days (Part 2)" </Td> <Td> Greg Yaitanes </Td> <Td> Krista Vernoff </Td> <Td> January 18, 2007 (2007 - 01 - 18) </Td> <Td> 21.94 </Td> </Tr> <Tr> <Td_colspan="7"> George learns about the procedure that Webber and Bailey performed on his father which ultimately leads to a worsening of his condition . The O'Malley family now have to face a difficult decision regarding Harold's inability to breathe on his own . They must take him off life support . Meredith finally talks to her father and realizes that her snoring is one of the many things they have in common, despite her inability to admit it . Meredith and Derek continue to argue over her snoring, but the situation is resolved following Meredith's talk with her dad . There's tension between Alex and Addison that eventually leads to them kissing . Addison confesses to Callie that she got pregnant with Mark's son but aborted him after realizing that Mark could never be a good father . Burke lets Cristina know about the status of his condition, but the pair still refuse to talk to each other . Izzie is barred from the girl's surgery after Bailey finds out that she paid for the operation, but she ultimately wins her respect after realizing that without the money the girl could have never been saved . The girl begins a new life as a normal child thanks to Izzie's generous donation . </Td> </Tr> <Tr> <Th> 49 </Th> <Td> 13 </Td> <Td> "Great Expectations" </Td> <Td> Michael Grossman </Td> <Td> Eric Buchman </Td> <Td> January 25, 2007 (2007 - 01 - 25) </Td> <Td> 21.50 </Td> </Tr> <Tr> <Td_colspan="7"> After Webber announces his retirement, rumors begin to circulate on his departure and successor . Mark is determined to leave Seattle for good, and irritates Meredith and Alex by making them tend to a patient who will need constant attention but Meredith accidentally gives Mark incentive to stay after letting him know of the open Chief position . Derek is angry at Meredith for causing Mark to remain in Seattle, but soon realizes that she is not the reason he is really angry . The attending physicians at Seattle Grace Hospital fight to get Webber's attention, but he expresses his disappointment in their conduct . He also forces Bailey to get signatures from all the attendings so she can create a free medical clinic, before confessing to her that he thinks she will be Chief one day . Bailey secures the signatures, but has no funding until Izzie offers to spend her entire 8.7 million dollar inheritance on the project . Addison, Izzie, and George treat a patient with a cervical tumor, and Izzie gets worried about George due to his dad having recently died from cancer . Things get more complicated when the patient's Puritan parents arrive . Addison is avoiding Alex following their kiss . Callie and Cristina treat a marathon runner who collapsed after a blackout . George, devastated after his father's death, reunites with Callie and uses sex to overcome his grief, before eventually proposing to her . Cristina and Burke still don't speak to each other, but she eventually breaks, and Burke ends up proposing to her . Webber endeavors to reunite with his wife, Adele, and decides to retire, only to come home and find she's with another man . </Td> </Tr> <Tr> <Th> 50 </Th> <Td> 14 </Td> <Td> "Wishin' and Hopin"' </Td> <Td> Julie Anne Robinson </Td> <Td> Tony Phelan & Joan Rater </Td> <Td> February 1, 2007 (2007 - 02 - 01) </Td> <Td> 24.18 </Td> </Tr> <Tr> <Td_colspan="7"> The race for the Chief's position is on, and the attending physicians, Derek, Burke, Addison, and Mark, compete for Webber's affections by trying to help out everywhere possible . The Denny Duquette Memorial Clinic is open for business, but no one shows up . Izzie is disappointed in what she invested Denny's legacy in, and she and Alex team up to steal patients from the emergency room . Callie and George get back from Las Vegas, announcing their marriage, much to everyone's disbelief . Izzie is not supportive of their marriage and tries to get George to realize the mistake he has made . George and Webber treat a patient with cancer, but her blood has a neurotoxin in it that causes all the staff around her to fall ill . The staff have to operate on her in hazmat suits, and later in small bursts to complete her surgery . Cristina doesn't give Burke an answer to his proposal, but after watching him risk his life during the surgery, she agrees to marry him . Meanwhile, Meredith's Alzheimer's - stricken mother, Ellis Grey, experiences a change in her medical condition by becoming lucid for the day . She is disappointed in the mediocrity her daughter has fallen into and begins to despise Derek, blaming him for what happened to the Meredith that used to be "a force of nature". Ellis has to have heart surgery and, despite her mother's wishes, Meredith schedules the upcoming surgery . Webber talks to Ellis and realizes that she is still in love with him, but she loses her memory after their talk ends, before Meredith has the chance to tell her how she really feels . </Td> </Tr> <Tr> <Th> 51 </Th> <Td> 15 </Td> <Td> "Walk on Water" </Td> <Td> Rob Corn </Td> <Td> Shonda Rhimes </Td> <Td> February 8, 2007 (2007 - 02 - 08) </Td> <Td> 25.20 </Td> </Tr> <Tr> <Td_colspan="7"> A mass trauma situation, which turns out to be a ferryboat accident, challenges the whole staff of Seattle Grace Hospital . Webber finds difficulty in coping with his separation from his wife and dyes his hair "for the ladies", which becomes an internal joke between Mark, Burke, and Derek . Cristina tries to tell Meredith about her upcoming marriage, but doesn't have the strength to . George promises to find a woman's son, who has been separated from her at the accident . The woman refuses to go into surgery until she is assured that her son is alive . Izzie has to take care of a man who got stuck between two cars on the ferry, but nobody helps her due to the large number of injured people . Alex rescues a pregnant woman with severe wounds on her face, and promises to take care of her . Meredith looks after a girl who has been separated from her mother after the accident and cannot communicate, but while helping a patient, he accidentally pushes Meredith, and she falls into the water, with nobody but the silent little girl as a witness . </Td> </Tr> <Tr> <Th> 52 </Th> <Td> 16 </Td> <Td> "Drowning on Dry Land" </Td> <Td> Rob Corn </Td> <Td> Shonda Rhimes </Td> <Td> February 15, 2007 (2007 - 02 - 15) </Td> <Td> 25.76 </Td> </Tr> <Tr> <Td_colspan="7"> Meredith struggles to stay afloat and eventually begins drowning, but nobody is around to notice . Derek finds her coat on a man she had helped, and starts looking for her and, much to his shock, the little girl Meredith took care of indicates that she is in the water . Derek saves her, but she is almost dead, due to hypothermia . The little girl gets reunited with her mother . Izzie has to perform brain surgery on a man stuck between cars, as he begins to experience seizures . She drills holes into his head, perforates his skull and ultimately saves his life before he is rescued and transferred to Seattle Grace Hospital; this leads to Webber allowing her back into surgeries . George lies to the woman whose son he had been looking for, in order to get her to surgery, and eventually finds Callie operating on the son . Alex is unsuccessful in searching for the pregnant Jane Doe's family as she undergoes surgery, and at the same time he also has to deal with the families of the victims . The interns find out about Meredith's situation and express their hopelessness . She wakes up in what appears to be limbo and meets her deceased acquaintances . </Td> </Tr> <Tr> <Th> 53 </Th> <Td> 17 </Td> <Td> "Some Kind of Miracle" </Td> <Td> Adam Arkin </Td> <Td> Shonda Rhimes & Marti Noxon </Td> <Td> February 22, 2007 (2007 - 02 - 22) </Td> <Td> 27.39 </Td> </Tr> <Tr> <Td_colspan="7"> Webber struggles to keep Meredith alive, whose body does not seem to respond to treatment, much to Derek's devastation . Meanwhile, a metaphor shows Meredith in what she believes is limbo, displaying her interacting with deceased acquaintances whose decision would influence her chances of survival . Cristina remedies her grief for Meredith by leaving the hospital and going shopping, while Alex continues to bond with the pregnant Jane Doe who remains unclaimed, due to her inability to remember anything . Derek is aware that Meredith is a good swimmer and blames Ellis Grey for her daughter's depression . Ellis goes into cardiac arrest and meets Meredith in the alternate universe, and declares her love and respect for her, telling her to wake up . She does so, and sees everyone who loves her by her side . Cristina lets her know about her engagement to Burke . Addison tells Mark that if he wants to reunite with her, he must go celibate for 60 days . </Td> </Tr> <Tr> <Th> 54 </Th> <Td> 18 </Td> <Td> "Scars and Souvenirs" </Td> <Td> James Frawley </Td> <Td> Debora Cahn </Td> <Td> March 15, 2007 (2007 - 03 - 15) </Td> <Td> 22.68 </Td> </Tr> <Tr> <Td_colspan="7"> The race between the attending physicians for the Chief of Surgery position heats up after a new competitor enters the fray . They soon realize that the new surgeon, Colin Marlow, was Cristina's professor in medical school and they used to have a long - term relationship . When Burke finds out about it he realizes that his and Cristina's relationship is on the rocks . George finds out that Callie's family is rich, but she had previously hidden the fact in order to find out whether George loves her for who she really is, which eventually leads to an argument toward the pair . Webber, Callie, and Izzie treat a war veteran with a bullet in his back . Derek treats his former colleague from New York, but they argue over the best care as Derek wants to push a risky surgery, and his colleague doesn't want any more surgeries . Alex continues to work with Jane Doe, whose memory hasn't come back, and later he moves into George's old room . Meredith and Derek have dinner with her father and stepmother . Meredith starts to connect with Susan, but her relationship with Thatcher seems to be irreparable . Izzie wakes up, realizing that she slept with George while they were both drunk . </Td> </Tr> <Tr> <Th> 55 </Th> <Td> 19 </Td> <Td> "My Favorite Mistake" </Td> <Td> Tamra Davis </Td> <Td> Chris Van Dusen </Td> <Td> March 22, 2007 (2007 - 03 - 22) </Td> <Td> 22.30 </Td> </Tr> <Tr> <Td_colspan="7"> In the aftermath of Izzie's affair with George, he doesn't seem to remember anything, and Izzie does her best to avoid Callie, but she becomes nervous when she has to help Callie and George treat a patient with FOP . Callie lets George know that they will be having dinner with her father, but George does not make a good impression, being hungover after last night's events . Alex helps Jane Doe choose what her face will look like after Mark performs reconstructive surgery on her . He also gives her a new perspective on how the world will see her from then on . The hospital board begins interviewing the candidates for the Chief's position, and Colin intimidates everyone with his ten - year plan . However, after taking advice from Bailey, Mark seems to have convinced the board that he is appropriate for the job, despite continuous efforts from Derek, Burke, and Addison, whose careers in the hospital outlast his . Cristina looks for a way to save a man's foot when he makes it clear that he doesn't want it amputated . Izzie seeks advice from Addison about her affair, confessing that sleeping with George felt right, despite him being married . Mark takes Meredith as his intern for the day in order to impress Webber, something that Derek doesn't approve of, feeling that Mark has become manipulative . </Td> </Tr> <Tr> <Th> 56 </Th> <Td> 20 </Td> <Td> "Time After Time" </Td> <Td> Christopher Misiano </Td> <Td> Stacy McKee </Td> <Td> April 19, 2007 (2007 - 04 - 19) </Td> <Td> 21.12 </Td> </Tr> <Tr> <Td_colspan="7"> When Izzie's daughter, Hannah Klein, is brought to the hospital for leukemia treatment, her adoptive parents come searching for Izzie, and ask her to donate her bone marrow in support . She is saddened to learn that her daughter does not want to see her, but is surprised to see how alike they are . George helps Izzie out, but forgets about a coffee break with Callie . Mark offers to be Webber's wingman, to get him back into dating . Derek comes to the conclusion that his relationship with Meredith is the only thing standing in his way to become the Chief of Surgery . Colin continues to intrude on Burke and Cristina's lives with an impending surgery he will perform . He tries to convince Cristina to break up with Burke, due to their targets being completely different . After realizing that Cristina has changed, Colin drops out of the race for Chief and leaves the hospital . Meredith starts to grow closer to her stepmother, Susan, but they experience a blip when Meredith snaps at her for her constant mothering . A couple arrives at Seattle Grace Hospital to see Ava, whom they initially believe to be their daughter, but the mother rejects Ava without telling her . They leave Alex to inform Ava, causing Ava to lash out . </Td> </Tr> <Tr> <Th> 57 </Th> <Td> 21 </Td> <Td> "Desire" </Td> <Td> Tom Verica </Td> <Td> Mark Wilding </Td> <Td> April 26, 2007 (2007 - 04 - 26) </Td> <Td> 20.08 </Td> </Tr> <Tr> <Td_colspan="7"> The interns of Seattle Grace Hospital start to use every free minute to study for their upcoming exam which will determine their entire residency in the surgical field . Cristina is jealous of George who can study with Callie, whose learning cards have become legendary . After the realization that George and Izzie might have feelings for each other, Callie decides to give the cards to Cristina . The attending physicians vie for the Chief position by tending to the chairman of the hospital board, after he is admitted as a patient . They soon learn that there is a fish in his urinary tract and learn that his wife has been aware of his affair with his secretary . She eventually resigns and leaves him, and his wife asks for divorce . In the clinic, Izzie treats a patient with a recurring cold, which turns out to be a symptom of something worse . Webber starts to question his decision to retire as he believes that there is a lot more he can do as a surgeon and cannot be done with his career in his early fifties . Cristina gets annoyed at Burke as he tries pressuring her into choosing a flavor for their wedding cake while she is trying to study . Addison and Alex deliver Ava's baby, through a cesarian - section, before sleeping together, but afterwards Alex tells her to make sure that it never happens again . Derek starts to question his relationship with Meredith, feeling that he is the only one putting an effort for it to work out . George tells Izzie that he is considering transferring to a different hospital . </Td> </Tr> <Tr> <Th> 58 59 </Th> <Td> 22 23 </Td> <Td> "The Other Side of This Life" </Td> <Td> Michael Grossman </Td> <Td> Shonda Rhimes </Td> <Td> May 3, 2007 (2007 - 05 - 03) </Td> <Td> 21.23 </Td> </Tr> <Tr> <Td_colspan="7"> After things become too complicated in Seattle, Addison travels to Los Angeles to reunite with her old friends from Columbia University College of Physicians and Surgeons . Much to her best friend's shock, the real reason for her visit is in order to get pregnant but she is devastated to learn that she cannot . Whilst there, Addison assists her friend in treating a surrogate mother, who had sex with three different men who all claim that the baby is theirs . Cristina finds difficulty in planning her wedding under the constant watch of her and Burke's mother, who are determined to create an extravagant wedding, despite her wishes of having a small ceremony . Callie is surprised to be invited to be Cristina's bridesmaid . Susan is admitted to the hospital, bringing Thatcher with her, but he suspects that she might be trying to bring Thatcher and Meredith together by faking hiccups . Mark talks to Derek and expresses his disappointment in not working things out with Addison, who he had truly fallen in love with . Burke is surprised when his mother tells him that he's making a mistake marrying Cristina, but she reassures him that she supports his decision . George is determined to transfer to Mercy West, despite Izzie's continuous begging . Addison becomes the temporary obstetrician - gynecologist at the Oceanside Wellness Center in Los Angeles and deals with the aftermath of the discovery that she cannot have children . She is comforted by Pete Wilder who flirts with and eventually kisses her . The doctors offer her a position, but she denies it after realizing that Seattle is where her life is . The Los Angeles team also continue to treat a man with no sex drive, which infuriates his wife, who has a high one . After Susan returns to the hospital with chest pain, she is rushed into emergency surgery and ultimately dies . Thatcher is devastated by the news and blames Meredith for her death, and slaps her . George and Burke confide in each other about their relationship problems, and Burke's intensify after an argument with his mother . Izzie finds difficulty in accepting that George is going to transfer because of her, but realizes that she can't deny her feelings towards him, which leads to them kissing . Meanwhile, Derek must perform surgery on Ava and she gets her hopes high after realizing that she might get her memory back . </Td> </Tr> <Tr> <Th> 60 </Th> <Td> 24 </Td> <Td> "Testing 1 - 2 - 3" </Td> <Td> Christopher Misiano </Td> <Td> Allan Heinberg </Td> <Td> May 10, 2007 (2007 - 05 - 10) </Td> <Td> 19.58 </Td> </Tr> <Tr> <Td_colspan="7"> The five interns finally have to face one of the biggest test of their careers, which will influence the rest of their lives as surgeons . Meredith is still feeling guilty about her stepmother's death, but feels confident that she will pass the exam, despite warnings from both Cristina and Richard . However, after her father, Thatcher, causes a scene at the hospital, Meredith finds herself unable to focus and doesn't write anything on the exam paper . Meanwhile, George gets accepted in the Mercy West Hospital surgical residency program and has to face a decision which will change his relationship with Izzie forever . Callie's suspicions of her husband's unfaithfulness grow, and is thrilled about George's transfer to a different hospital . Alex learns that Ava's memory has come back, but he becomes infuriated with her after learning that she is not willing to let her family know where she is . Bailey realizes that Callie's chances of becoming Chief Resident have increased considerably, while Burke cannot get Cristina to talk to him about their upcoming wedding . The attending physicians work with three injured mountain climbers who left their friend behind in order to save their own lives . Derek continues to feel pushed out by Meredith, and at Burke's stag party he flirts with another woman . Joe and his boyfriend consider adopting a baby, but things go bad for them when their surrogate mother collapses . Addison makes the shocking discovery that Adele, Webber's wife, is pregnant . Webber eventually bumps into her, but Adele hides in the ladies' bathroom, and when he finally enters he finds her collapsed on the floor . </Td> </Tr> <Tr> <Th> 61 </Th> <Td> 25 </Td> <Td> "Didn't We Almost Have It All?" </Td> <Td> Rob Corn </Td> <Td> Tony Phelan & Joan Rater </Td> <Td> May 17, 2007 (2007 - 05 - 17) </Td> <Td> 22.57 </Td> </Tr> <Tr> <Td_colspan="7"> The mountain climbers lie about the axe in their friend's head, telling Derek that it accidentally got there . During surgery, he and George discover that it was deliberately put there, and one of the climbers admits that he was trying to "put him out of his misery". Adele is stabilized following her collapse, but she soon suffers a miscarriage . Webber learns Adele was actually pregnant with his son, not someone she had one night stand with . Bailey is disappointed to see that Callie is the new Chief Resident and begins to question her abilities as a surgeon . Callie tells George she wants a baby . Webber chooses Derek as Chief of Surgery, but he refuses, telling Webber that he should continue . Ava's husband shows up at the hospital to find her, but when he's gone, Ava confesses to Alex that she wants to be with him, but he turns her down . Cristina and Burke's wedding day arrives, but Cristina won't stay out of the hospital . However, Cristina's nervousness results in Burke realizing that he does not love the real Cristina, and leaves her . Meredith and Derek are uncertain about their future . George fails his internship exam . </Td> </Tr> </Table> <Tr> <Th> No . overall </Th> <Th> No. in season </Th> <Th> Title </Th> <Th> Directed by </Th> <Th> Written by </Th> <Th> Original air date </Th> <Th> U.S. viewers (millions) </Th> </Tr>

When does meredith and derek get back together in season 3