<Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td_colspan="2"> 23 </Td> <Td_colspan="1"> October 4, 2016 (2016 - 10 - 04) </Td> <Td> May 23, 2017 (2017 - 05 - 23) </Td> <Td> 120 </Td> <Td> 3.50 </Td> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td_colspan="2"> 23 </Td> <Td_colspan="1"> October 10, 2017 (2017 - 10 - 10) </Td> <Td> May 22, 2018 (2018 - 05 - 22) </Td> <Td> TBA </Td> <Td> TBA </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> Prod . code </Th> <Th> U.S. viewers (millions) </Th> </Tr> <Tr> <Th> </Th> <Td> </Td> <Td> "Pilot" </Td> <Td> David Nutter </Td> <Td> Story by: Greg Berlanti & Andrew Kreisberg & Geoff Johns Teleplay by: Andrew Kreisberg & Geoff Johns </Td> <Td> October 7, 2014 (2014 - 10 - 07) </Td> <Td> 296648 </Td> <Td> 4.83 </Td> </Tr> <Tr> <Td_colspan="8"> Barry Allen, a forensic crime scene assistant for Central City Police Department, is struck by lightning during a storm that is created after a particle accelerator from S.T.A.R. Labs explodes . In a coma for nine months, Barry awakens in S.T.A.R. Labs, having been placed in the care of Dr. Harrison Wells and his assistants Dr. Caitlin Snow and Cisco Ramon . Barry learns that he can move at extraordinary speeds, and that there were other "metahumans" created from the explosion . One of them, Clyde Mardon, is robbing banks with his ability to control the weather . In order to stop Mardon, Barry is outfitted with a suit, designed by Cisco, that can withstand his high speed . He tracks down Mardon and with Detective Joe West, who learns of Barry's abilities, Barry is able to stop Mardon, who is killed by Joe . With his new powers, Barry vows to exonerate his father, Henry, who is incarcerated for the accusation of murdering his wife, Nora, whom Barry witnessed being killed by another metahuman . He chooses the alias "Flash" for his alter ego . Wells, secretly revealed to be neither paraplegic nor needing glasses, reads a newspaper from 2024 stating the missing status of the Flash . </Td> </Tr> <Tr> <Th> </Th> <Td> </Td> <Td> "Fastest Man Alive" </Td> <Td> David Nutter </Td> <Td> Story by: Greg Berlanti & Andrew Kreisberg Teleplay by: Andrew Kreisberg & Geoff Johns </Td> <Td> October 14, 2014 (2014 - 10 - 14) </Td> <Td> 3J5352 </Td> <Td> 4.27 </Td> </Tr> <Tr> <Td_colspan="8"> In flashbacks, it is revealed that Joe became Barry's legal guardian but did not let him visit Henry in prison at the latter's request . Barry begins using his abilities to stop minor crimes and help citizens across the city while starting to develop debilitating side effects . While guiding Iris West, who seeks his help to do her school assignment, Barry witnesses a robbery by a crew of men, but passes out while trying to stop them . The S.T.A.R. Labs team determines that Barry becomes hypoglycemic from the use of his abilities due to a sped - up metabolism and needs to ingest more calories to maintain his energy level . The team eventually learns that there is actually one robber, Danton Black, who has the ability to create clones of himself . Black intends to kill his former employer Simon Stagg, who stole Black's cloning research . With encouragement from Joe, Barry goes after Black and successfully stops him . However, Black commits suicide . Afterward, Barry accepts Joe's help in the investigation of Nora's murder . Later, Wells visits Stagg, who has already become obsessed with the Flash and plans to exploit them as he did to Black . Wells then kills Stagg . </Td> </Tr> <Tr> <Th> </Th> <Td> </Td> <Td> "Things You Can't Outrun" </Td> <Td> Jesse Warn </Td> <Td> Alison Schapker & Grainne Godfree </Td> <Td> October 21, 2014 (2014 - 10 - 21) </Td> <Td> 3J5353 </Td> <Td> 3.59 </Td> </Tr> <Tr> <Td_colspan="8"> As the police investigate the murder of one of the city's crime families, Barry suspects that the killer may be a metahuman who can control poison gases . As Barry and Joe work to discover the killer's identity, Wells and his team work to retrofit the particle accelerator into a prison for metahumans where they can begin to find a way of reversing their mutations . This brings up difficult feelings and memories for Snow, whose fiancé, Ronnie Raymond, was killed by the explosion . The team identifies the killer as Kyle Nimbus, discovering that Nimbus does not control gases, but transforms his body into them . The team learns that Joe, the lead detective in the original case, is Nimbus' next target . Barry races to Iron Heights Prison to save Joe's life, forcing Nimbus to overexert himself so that he can apprehend him . The team locks Nimbus into a cell they have made . In a flashback to when the accelerator explodes, Wells is seen going into his hidden room and viewing a surveillance video of Barry getting struck by lightning in his lab . </Td> </Tr> <Tr> <Th> </Th> <Td> </Td> <Td> "Going Rogue" </Td> <Td> Glen Winter </Td> <Td> Geoff Johns & Kai Yu Wu </Td> <Td> October 28, 2014 (2014 - 10 - 28) </Td> <Td> 3J5354 </Td> <Td> 3.53 </Td> </Tr> <Tr> <Td_colspan="8"> Wells begins testing Barry's powers by having him perform multiple tasks at superspeed . In the middle of the tests, a group of men attempt to hijack an armored truck carrying a diamond . Barry races over and stops the crime, as well as identifying Leonard Snart from a set of police mugshots . Felicity Smoak arrives to check on Barry, after learning that he woke from his coma . Barry introduces her to his friends at S.T.A.R. Labs . To combat the Flash, also known as the "Streak", Snart acquires stolen tech from S.T.A.R. Labs, which includes a cryonic gun . Cisco reveals to Barry that he created the gun as a fail - safe against Barry should he become a villain like the other metahumans they have encountered . Felicity helps the team locate Snart, who sets a trap for Barry . Cisco, Caitlin, and Felicity arrive in time to save Barry, and Snart is able to escape . Joe finally accepts Iris's relationship with Eddie Thawne, his partner . Wells demands Cisco not to build another fail - safe against Barry again . Later, Snart tracks down his former partner, who has an affinity for fire, and offers him a place by Snart's side taking back Central City from the Flash . </Td> </Tr> <Tr> <Th> 5 </Th> <Td> 5 </Td> <Td> "Plastique" </Td> <Td> Dermott Downs </Td> <Td> Aaron Helbing & Todd Helbing & Brooke Eikmeier </Td> <Td> November 11, 2014 (2014 - 11 - 11) </Td> <Td> 3J5355 </Td> <Td> 3.46 </Td> </Tr> <Tr> <Td_colspan="8"> Bette Sans Souci, a metahuman with the ability to turn anything she touches into an explosive, appears in Central City . She is being hunted by General Wade Eiling, and is a former military explosives expert . Barry brings her to S.T.A.R. Labs where the team explains to her that she was changed by the particle accelerator, which bonded bomb shrapnel to her body on a cellular level; and they cannot reverse the process . Secretly, Wells convinces Bette to kill Eiling . Barry races to stop her, and Eiling shoots her, who dies after mentioning Wells' name . Her body turns into a bomb . Barry speeds off with the body and drops it in the river to save the city from the massive explosion . Eiling visits Wells, demanding that they work together once again, this time to collect metahumans . Wells refuses and warns Eiling to never return to S.T.A.R. Labs . Meanwhile, Barry ends his friendship with Iris after she refuses his advice not to write about the "Streak". In a flashback set five years previously, Wells tells Eiling he is ending their experiments . After Eiling leaves, Wells walks to a cage and tells Gorilla Grodd that he has plans for him . </Td> </Tr> <Tr> <Th> 6 </Th> <Td> 6 </Td> <Td> "The Flash Is Born" </Td> <Td> Millicent Shelton </Td> <Td> Jaime Paglia & Chris Rafferty </Td> <Td> November 18, 2014 (2014 - 11 - 18) </Td> <Td> 3J5356 </Td> <Td> 3.73 </Td> </Tr> <Tr> <Td_colspan="8"> Barry speeds off to stop a car thief; but the thief's skin turns to steel and Barry breaks his hand while punching . He runs back to the lab before he can be hurt further . The thief is identified as Tony Woodward, Barry's childhood bully . Back at the lab, Cisco determines that if Barry can hit Woodward with a specific velocity at right angle, then he can create enough force to compromise Woodward's metal structure . Woodward kidnaps Iris and demands that she write about him . Barry arrives and manages to temporarily disable Woodward's abilities . Afterward, Woodward is locked away at S.T.A.R. Labs and finds out that Barry is the Flash, the name Iris also uses in her blog on the advice of Barry, who reconciles with her . Meanwhile, Joe continues investigating Nora's murder and gets suspicious of Wells, who opened S.T.A.R. Labs one month after Nora's murder; but Wells states that he came to Central City because of his wife's death . Joe, convinced that Wells is not involved, is visited by the metahuman that killed Nora, stealing the case file and threatening Iris's life if Joe does not drop his investigation . </Td> </Tr> <Tr> <Th> 7 </Th> <Td> 7 </Td> <Td> "Power Outage" </Td> <Td> Larry Shaw </Td> <Td> Alison Schapker & Grainne Godfree </Td> <Td> November 25, 2014 (2014 - 11 - 25) </Td> <Td> 3J5357 </Td> <Td> 3.47 </Td> </Tr> <Tr> <Td_colspan="8"> Wells returns to his secret room, where it is revealed that he has been documenting Barry's abilities, and using his artificial intelligence, Gideon, to look at events in the future . Barry arrives at a crime scene where the victim was murdered via electrocution, and charred beyond recognition, suggesting a metahuman was involved . While investigating the victim's identity, the team identifies a power drain in the city . When Barry arrives, he is attacked by Farooq Gibran, a man who has the ability to siphon electrical energy . The attack drains Barry of his speed, and Gideon reveals to Wells that there are currently no references to the Flash in the future . Wells realizes that Barry's problem is psychological . Gibran attacks S.T.A.R. Labs, kills Woodward and Wells' life gets in danger, forcing Barry to overcome his fear, connect to his speed and kill Gibran . Meanwhile, Tockman starts a hostage crisis at a police station and critically shoots Eddie; but Iris manages to stop him and he is rearrested . Later, Wells sees that the timeline is safe, and takes a sample of Gibran's blood to determine how he was able to drain Barry's abilities . </Td> </Tr> <Tr> <Th> 8 </Th> <Td> 8 </Td> <Td> "Flash vs. Arrow" </Td> <Td> Glen Winter </Td> <Td> Story by: Greg Berlanti & Andrew Kreisberg Teleplay by: Ben Sokolowski & Brooke Eikmeier </Td> <Td> December 2, 2014 (2014 - 12 - 02) </Td> <Td> 3J5358 </Td> <Td> 4.34 </Td> </Tr> <Tr> <Td_colspan="8"> <P> Eddie proposes a task force to hunt down the Flash . A new metahuman, Roy Bivolo, shows up with the ability to send people into an uncontrollable rage, and uses his ability to rob a bank . Oliver Queen informs Barry that he and his team are tracking a killer who uses lethal boomerangs . Barry and Oliver agree to team - up and catch each other's targets . Barry decides to go after Bivolo by himself . Bivolo uses his abilities on Barry; but because of Barry's powers it makes the effects last longer . Oliver tries to stop Barry, and the two engage in a fight until Wells and Joe use colored strobe light to reset Barry's emotional state . Afterward, Barry and Oliver capture Bivolo and place him in the prison at S.T.A.R. Labs . Eddie's task force is established after he was beaten by an enraged Flash . Barry confirms Oliver's belief that he has a lot to learn . Oliver advises him to stay away from Iris, whom Barry is in love with . Iris decides to end her support of the Flash . Oliver asks Barry's team to keep his alter ego a secret . A new metahuman able to manipulate fire appears in Central City . </P> This episode begins a crossover event that concludes on Arrow season 3 episode 8 . </Td> </Tr> <Tr> <Th> 9 </Th> <Td> 9 </Td> <Td> "The Man in the Yellow Suit" </Td> <Td> Ralph Hemecker </Td> <Td> Todd Helbing & Aaron Helbing </Td> <Td> December 9, 2014 (2014 - 12 - 09) </Td> <Td> 3J5359 </Td> <Td> 4.66 </Td> </Tr> <Tr> <Td_colspan="8"> The yellow - suited speedster who killed Nora Allen returns, in search of Mercury Lab's tachyon particle technology . Barry encounters the "Reverse - Flash" and engages him but is swiftly defeated, with the villain insinuating that he and Barry have been lifelong enemies . Ronnie is revealed as the flame - controlling metahuman, suffering from memory - loss after having survived the explosion . Per Henry's advice, Barry confesses his love for Iris before the tachyon particle technology is used as bait to lure the Reverse - Flash into a trap . The villain manages to escape, however, and proceeds to attack Wells and the police, mysteriously sparing Eddie before engaging in Barry again . Ronnie appears and fends off the Reverse - Flash before they both flee the scene . Joe tells Eddie about metahumans and asks him to keep it a secret . Cisco realizes that there were two speedsters in Barry's house the night Nora died . Later, Wells enters his secret room and reveals the Reverse - Flash suit in a hidden chamber . Wells places the stolen tachyon device on it, and speaks in the villainous speedster's distorted voice, revealing himself to be the Reverse - Flash . </Td> </Tr> <Tr> <Th> 10 </Th> <Td> 10 </Td> <Td> "Revenge of the Rogues" </Td> <Td> Nick Copus </Td> <Td> Kai Yu Wu & Geoff Johns </Td> <Td> January 20, 2015 (2015 - 01 - 20) </Td> <Td> 3J5360 </Td> <Td> 3.87 </Td> </Tr> <Tr> <Td_colspan="8"> As Barry works on improving his speed through various training exercises, Leonard Snart returns to Central City with the cold gun and a new partner, Mick Rory, to set a trap for the Flash . Barry discovers his plan, and agrees with Wells not to engage Snart in the hope that he goes away and no one gets hurt like the last time . Snart and Rory, who now has a gun that can emit absolute hot temperatures, kidnap Caitlin to force Barry out of hiding . Cisco and Barry find a way to defeat Snart and Rory . The Flash faces the duo in the city for a showdown, exposing himself to the public . Barry eventually gets them to cross their streams with Eddie's help, successfully damaging the weapons and disabling the pair, who are arrested and the guns delivered to S.T.A.R. Labs . While in transport to Iron Heights, Snart and Rory are broken out by Snart's sister . Meanwhile, Caitlin investigates the cause of Ronnie's transformation and finds out that the Army is covering up the incident . After Iris moves in with Eddie, Barry decides to move back in with Joe . </Td> </Tr> <Tr> <Th> 11 </Th> <Td> 11 </Td> <Td> "The Sound and the Fury" </Td> <Td> John F. Showalter </Td> <Td> Alison Schapker & Brooke Eikmeier </Td> <Td> January 27, 2015 (2015 - 01 - 27) </Td> <Td> 3J5361 </Td> <Td> 4.08 </Td> </Tr> <Tr> <Td_colspan="8"> While home, Wells receives a threatening call from an unidentified person before using his super speed to save his life from an attempt . Wells informs Barry and the team that the caller was Hartley Rathaway, a former protégé . Rathaway begins attacking his family's business with sonic blasts, and after Barry stops him, Rathaway reveals that he knows a secret of Wells', who states that Rathaway warned him that the particle accelerator could explode, but Wells chose to risk it for the rewards . Cisco discovers that Rathaway intentionally got caught so he could steal information from S.T.A.R. Labs that would allow him to identify the frequency of Barry's molecules so he can kill him . A trap set by Rathaway starts shredding Barry's organs . Wells manages to disable Rathaway's weapons . Later, Joe has Eddie start an investigation into Wells . Rathaway, imprisoned back in the particle accelerator, reveals to Cisco that he knows where Ronnie is and how to save him . In his secret room, Wells uses the tachyon technology to temporarily recharge his speed force energy . Meanwhile, Iris starts working as a journalist and realizes that she is hired to write about the Flash . </Td> </Tr> <Tr> <Th> 12 </Th> <Td> 12 </Td> <Td> "Crazy for You" </Td> <Td> Rob Hardy </Td> <Td> Aaron Helbing & Todd Helbing </Td> <Td> February 3, 2015 (2015 - 02 - 03) </Td> <Td> 3J5362 </Td> <Td> 3.60 </Td> </Tr> <Tr> <Td_colspan="8"> A woman with the ability to teleport to any location she can see breaks into Iron Heights and frees her boyfriend, Clay Parker . The S.T.A.R. Labs team identifies the woman as Shawna Baez . To help Barry, Henry tracks down leads in Iron Heights and finds out that Parker owed money to a local crime boss and is planning a heist to pay it back . Barry learns the location of the heist, finding Baez and Parker and is able to capture her after removing all the lights in a tunnel, effectively making her unable to teleport without being able to see . Parker manages to escape . Meanwhile, Cisco brings Rathaway out of his cell so that the latter can show the truth about Ronnie; Rathaway reveals that Doctor Martin Stein, who developed research into a F.I.R.E.S.T.O.R.M. project focused on transmuting elements, was at S.T.A.R. Labs the day of the explosion . Rathaway reveals that during the explosion Ronnie and Stein merged, before he escapes Cisco's custody . Barry starts dating Iris's colleague, Linda Park . Henry insinuates to Barry that he knows Barry's alter ego . Elsewhere, two city workers are attacked by Grodd . </Td> </Tr> <Tr> <Th> 13 </Th> <Td> 13 </Td> <Td> "The Nuclear Man" </Td> <Td> Glen Winter </Td> <Td> Andrew Kreisberg & Katherine Walczak </Td> <Td> February 10, 2015 (2015 - 02 - 10) </Td> <Td> 3J5363 </Td> <Td> 3.66 </Td> </Tr> <Tr> <Td_colspan="8"> The team attempts to track Stein's whereabouts after he attacks a scientist . They convince Stein into coming back to S.T.A.R. Labs for testing . Wells discovers that Ronnie and Stein's atoms are in conflict, and if it continues they will become nuclear . Stein leaves for a secluded location to safely explode without casualties . Barry and Caitlin arrive and use a device Wells made from the tachyon to separate the bodies, but it apparently does not work, and the duo escapes the explosion, which alerts Eiling, who orders a team to recover "Firestorm". Meanwhile, Joe enlists Cisco's help to identify Nora's murderer . The duo searches the house and finds blood from two people behind some new wallpaper . Joe asks Cisco to compare the blood to Wells' . Cisco runs the blood and informs Joe that while neither is from Wells, one is from an adult Barry . In the meantime Linda believes Barry to be still in love with Iris, but he proves to Linda that he now loves her not Iris . </Td> </Tr> <Tr> <Th> 14 </Th> <Td> 14 </Td> <Td> "Fallout" </Td> <Td> Steve Surjik </Td> <Td> Keto Shimizu & Ben Sokolowski </Td> <Td> February 17, 2015 (2015 - 02 - 17) </Td> <Td> 3J5364 </Td> <Td> 4.01 </Td> </Tr> <Tr> <Td_colspan="8"> Barry and Caitlin find Ronnie and Stein alive and separated, which Eiling also finds out . Joe reveals his findings to Barry . Ronnie and Stein realize that their minds are partially connected . Wells visits Eiling, who reveals that he knows Barry's alter ego and demands the F.I.R.E.S.T.O.R.M. project . Wells gives up Stein, who is tortured by Eiling until Barry and Ronnie save him . Ronnie and Stein reunite by the tachyon piece to survive the military onslaught . The duo gains enough control to be able to merge and separate on command . They decide to leave Central City to stay ahead of Eiling and learn more about their new powers . As the Reverse - Flash, Wells kidnaps Eiling and brings him to the sewers . He reveals himself to Eiling, and allows Grodd, who is displaying psychic abilities, to drag Eiling deeper into the sewer . Meanwhile, Iris's colleague, Mason Bridge tells her his belief that Wells deliberately caused the S.T.A.R. Labs explosion . Iris suspects Caitlin's activities and decides to help Mason with his investigation . Barry tells Joe that he will travel back in time again to save Nora, but intends to succeed by learning the mistakes in his previous attempt . </Td> </Tr> <Tr> <Th> 15 </Th> <Td> 15 </Td> <Td> "Out of Time" </Td> <Td> Thor Freudenthal </Td> <Td> Todd Helbing & Aaron Helbing </Td> <Td> March 17, 2015 (2015 - 03 - 17) </Td> <Td> 3J5365 </Td> <Td> 3.69 </Td> </Tr> <Tr> <Td_colspan="8"> Mark Mardon, Clyde's brother, returns to Central City to avenge Clyde's death . Eddie and Linda get jealous of the intimacy between Barry and Iris . Mason shares his knowledge that Wells killed Stagg with Iris and Barry, who tells Caitlin and Cisco, who begins to believe Joe was right about Wells, so he rechecks the containment field that failed to hold the Reverse - Flash . Wells arrives and reveals himself to be Eobard Thawne, a relative of Eddie's and a man from the future who came back in time to kill Barry, and has since been stranded in the present day . Thawne also explains that he is pushing Barry to get stronger so that he can use Barry's powers to return to his time, and he murders Cisco to protect his secret . Mardon kidnaps Joe and forces him to watch as Mardon creates a tsunami in order to kill Iris . Barry reveals his secret identity to Iris, just after they admit to romantic feelings for each other, in order to save the city . Barry runs back and forth across the coastline to create a barrier against the tsunami, but he runs so fast that he travels back in time to the day before . </Td> </Tr> <Tr> <Th> 16 </Th> <Td> 16 </Td> <Td> "Rogue Time" </Td> <Td> John Behring </Td> <Td> Story by: Grainne Godfree Teleplay by: Brooke Eikmeier & Kai Yu Wu </Td> <Td> March 24, 2015 (2015 - 03 - 24) </Td> <Td> 3J5366 </Td> <Td> 3.33 </Td> </Tr> <Tr> <Td_colspan="8"> Thawne warns Barry not to change any event for fear that he will create a bigger problem . Barry does not listen and instead captures Mardon and puts him in the particle accelerator . Snart and Rory return to Central City . Snart sends his sister, Lisa after Cisco, whom they force to rebuild the cold and heat guns, and a third gun shooting gold for Lisa, by threatening to kill Cisco's brother . Iris rejects Barry's romantic approach and later Eddie punches him . Barry realizes that Thawne was right about not to manipulate the timeline . Cisco returns and reveals that Snart forced him to reveal the Flash's true identity . Barry goes after Snart, and the two come to a truce: Snart will not reveal Barry's identity, will no longer kill innocent people, and stay away from Barry's loved ones in exchange for Barry not locking him away in the particle accelerator . Caitlin tells Eddie and Iris that Barry is suffering from psychosis as a result of the lightning, making the duo reconcile with him and settling the tension . The Reverse - Flash kills Mason and destroys the evidence linking Thawne to Stagg's death . Mason's vanishing causes Barry to accept Joe was right about "Wells". </Td> </Tr> <Tr> <Th> 17 </Th> <Td> 17 </Td> <Td> "Tricksters" </Td> <Td> Ralph Hemecker </Td> <Td> Andrew Kreisberg </Td> <Td> March 31, 2015 (2015 - 03 - 31) </Td> <Td> 3J5367 </Td> <Td> 3.67 </Td> </Tr> <Tr> <Td_colspan="8"> Barry and Joe go after terrorist Axel Walker, under the alias Trickster . Walker sets a diversion for the Flash and breaks James Jesse, the original Trickster from 20 years prior, out of prison . Jesse and Walker attempt to extort patrons of fundraiser by poisoning them and ransoming the antidote . When the Flash arrives, Jesse and Walker fit him with a bomb that will detonate if he stops moving . Thawne coaches Barry on how to vibrate his molecules so that he can phase through objects, which removes the bomb . Afterward, Barry provides an antidote to all the patrons before capturing Jasse and Walker . The Flash reveals his identity to Eddie and convinces him to keep Iris from investigating Mason's disappearance . Barry tells Eddie and Joe that "Wells" is the Reverse - Flash . In flashbacks, after failing to kill Barry, the Reverse - Flash escapes only to lose his speed . Gideon informs him that travelling through time has drained his powers . Thawne kills Harrison Wells and steals his appearance and identity so he can develop the particle accelerator sooner and return to his timeline . </Td> </Tr> <Tr> <Th> 18 </Th> <Td> 18 </Td> <Td> "All Star Team Up" </Td> <Td> Kevin Tancharoen </Td> <Td> Grainne Godfree & Kai Yu Wu </Td> <Td> April 14, 2015 (2015 - 04 - 14) </Td> <Td> 3J5368 </Td> <Td> 3.67 </Td> </Tr> <Tr> <Td_colspan="8"> As Barry works in conjunction with Joe and Eddie to stop crimes across the city, an engineering professor is killed by a swarm of bees at a university . While the team searches for a metahuman that can control bees, Felicity arrives with Ray Palmer, looking for assistance to improve his A.T.O.M. suit . The team tracks another bee attack, but Barry is too late and is attacked by the swarm . The team captures one of the bees, which turns out to be a robot and their suspect just a scientist from Mercury Labs named Brie Larvan, who is targeting other former employees . During the next bee attack, Barry goes after Larvan while Ray attempts to stop the bees from killing Dr. Tina McGee . Felicity disables the robots, and Barry captures Larvan . Tina tells Barry that "Wells" personality changed after his wife's demise . Iris threatens Eddie to break up if he does not share his secret . Barry informs Caitlin and Cisco about "Wells". She does not want believe it, but Cisco does, revealing that he has been having "dreams", which show his final moments with Thawne in the alternate timeline . </Td> </Tr> <Tr> <Th> 19 </Th> <Td> 19 </Td> <Td> "Who Is Harrison Wells?" </Td> <Td> Wendey Stanzler </Td> <Td> Ray Utarnachitt & Cortney Norris </Td> <Td> April 21, 2015 (2015 - 04 - 21) </Td> <Td> 3J5369 </Td> <Td> 3.75 </Td> </Tr> <Tr> <Td_colspan="8"> Barry and Eddie track a metahuman named Hannibal Bates, who can shape - shift into anyone he touches . Bates takes Eddie's shape and frames him for murder . Later, Bates knocks Barry unconscious and assumes his form, but Thawne realizes the truth and prevents Bates from killing Caitlin and Iris . Bates manages to escape . Caitlin develops a serum to suppress Bates' power, allowing Barry to defeat him and clear Eddie's name . Iris reconciles with Eddie, who reveals his cooperation with the Flash . Bates is locked in the particle accelerator . Meanwhile, Joe and Cisco decide to investigate the car accident scene in Starling City where Dr. Wells' wife died . With the help of Captain Quentin Lance, Cisco and Joe locate a buried corpse near the crash site . Cisco also modifies a sonic device for Laurel . Joe advises Quentin to reconcile with her . After a series of tests confirm the corpse is the real Dr. Wells, Barry, Caitlin and Cisco locate Thawne's secret room at S.T.A.R. Labs . They find both the Reverse - Flash's costume and the newspaper article from 2024 . </Td> </Tr> <Tr> <Th> 20 </Th> <Td> 20 </Td> <Td> "The Trap" </Td> <Td> Steve Shill </Td> <Td> Alison Schapker & Brooke Eikmeier </Td> <Td> April 28, 2015 (2015 - 04 - 28) </Td> <Td> 3J5370 </Td> <Td> 3.93 </Td> </Tr> <Tr> <Td_colspan="8"> Barry talks to Gideon and learns about his battle with the Reverse - Flash in the future, as well as key moments in his life that include marrying Iris, a promotion at the CCPD, and that he created Gideon in the future . With high - tech goggles, the team reawakens Cisco's memories of his alternate - timeline death and the secrets Wells confessed . The team regroups at Joe's house, where Barry reveals his recent time travel and explains his plan to lure Thawne to confess to killing Nora . To trap Thawne, Cisco reverses the polarity of his containment field to protect himself from Thawne, while Caitlin films the interaction to capture Thawne's confession . The trap fails, but Joe shoots Thawne before he can kill Cisco . As Thawne dies, his body transforms, revealing himself to be Bates . Thawne himself calls the team, revealing that he was always aware of their actions because he had them under surveillance . Reverse - Flash goes after Iris and Eddie, but Barry arrives, forcing Thawne to kidnap Eddie instead . Iris finds out about the Flash's identity . Thawne reveals his relation to Eddie . Flashbacks reveal the aftermath of Barry being struck by lightning, and Thawne convincing Joe to let him save Barry's life, and promising to a comatose Barry that he will die . </Td> </Tr> <Tr> <Th> 21 </Th> <Td> 21 </Td> <Td> "Grodd Lives" </Td> <Td> Dermott Downs </Td> <Td> Grainne Godfree & Kai Yu Wu </Td> <Td> May 5, 2015 (2015 - 05 - 05) </Td> <Td> 3J5371 </Td> <Td> 3.62 </Td> </Tr> <Tr> <Td_colspan="8"> While looking for Eddie and Eobard, Barry heads to stop a robbery at the gold reserve . When Barry confronts the would - be thief, they are both disoriented by an unknown psychological attack . Back at S.T.A.R. Labs, Iris confronts Barry about being the Flash . He is able to stop the thief, who turns out to be Eiling, whose mind is revealed to be controlled by Grodd . With a lead from Iris, Barry, Joe and Cisco head into the sewers to look for Grodd . The trio realize that Grodd is getting smarter and larger, and during an attack, Joe is kidnapped by Grodd . Cisco and Caitlin build Barry a device that will prevent Grodd's effect . It works, but the device gets damaged in a fight . Barry is able to fight off Grodd's psychic attack and trick him into jumping in front of an on - coming train . Eiling is freed . Iris reveals her feelings for Barry, but states her choice to be with Eddie . Grodd is revealed to be safe and roaming the streets . Meanwhile, Thawne works on a device that will allow him to return to his own time . He reveals to Eddie, Iris and Barry's marriage in the future . Later Thawne completes the device and is revealed to be hiding in a secret chamber inside S.T.A.R. Labs . </Td> </Tr> <Tr> <Th> 22 </Th> <Td> 22 </Td> <Td> "Rogue Air" </Td> <Td> Doug Aarniokoski </Td> <Td> Aaron Helbing & Todd Helbing </Td> <Td> May 12, 2015 (2015 - 05 - 12) </Td> <Td> 3J5372 </Td> <Td> 3.65 </Td> </Tr> <Tr> <Td_colspan="8"> Cisco discovers that Eobard has been supercharging his speed through his wheelchair, which is why he is so much faster than Barry . The particle accelerator is activated by Eobard, who has managed to repair it . The team is able to find and rescue Eddie, who ends his relationship with Iris . Worried that the metahumans imprisoned inside the particle accelerator will be killed when it reaches full power, the team plans to relocate them to Oliver's prison on Lian Yu . In order to set up a safe transport, Barry requests Leonard's help . Leonard agrees but only after Barry erases all of Leonard's criminal record . Leonard and Lisa sabotage the transport and allow the metahumans to escape, killing Simmons however . Eobard arrives back at the lab just as the accelerator fully charges . Barry, Firestorm and Oliver all meet outside to fight Reverse - Flash . They coordinate their efforts; Oliver stops him with a nanite injection that disables Eobard's speed and knocks him out . Oliver leaves after informing Barry of an upcoming help request . </Td> </Tr> <Tr> <Th> 23 </Th> <Td> 23 </Td> <Td> "Fast Enough" </Td> <Td> Dermott Downs </Td> <Td> Story by: Greg Berlanti & Andrew Kreisberg Teleplay by: Gabrielle Stanton & Andrew Kreisberg </Td> <Td> May 19, 2015 (2015 - 05 - 19) </Td> <Td> 3J5373 </Td> <Td> 3.87 </Td> </Tr> <Tr> <Td_colspan="8"> Barry visits Thawne in the particle accelerator prison, where Thawne reveals he killed Nora because of hating the Flash, whose future self saved him . Eobard requests Barry to help create a wormhole where Thawne can return to his time, while also allowing Barry to save Nora . Caitlin and Ronnie get married . Eobard tells Cisco that the latter's ability to recall events of alternate timelines was acquired from the particle accelerator explosion . Barry decides to go through with Thawne's offer . The latter states that Barry will have only a short time, or else the wormhole will become a black hole . Barry travels back in time, but his future self signals him not to save Nora . The present Barry returns and stops Thawne from returning to his time . The two fight, while the team shuts down the wormhole . Thawne eventually prevails, but before he can kill Barry, Eddie shoots himself, causing Thawne's existence to cease . The wormhole reappears, and the team is unable to prevent it from becoming a black hole . As the black hole begins to tear the city apart, pulling Eddie inside, Barry speeds into it in an effort to stop it . </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> Prod . code </Th> <Th> U.S. viewers (millions) </Th> </Tr>

When does episode 16 of the flash air