<P> In Season 2 Brennan shot and killed a person for the first time while working on a string of murders connected to serial killer Howard Epps . She was forced to pull the trigger after Epps' accomplice attacked and injured Booth with a pipe . At the end of the episode she confides in Booth of her conflicted feelings and finds comfort in the fact that Booth understood how she felt . </P> <P> The relationship between Brennan and Booth has often become strained when either partner has a significant other . For example, Booth was quite irritable when Brennan dated Agent Sully, and their relationship was also strained when Booth's brother Jared was showing an interest in Brennan . Brennan constantly needled Booth while he was dating Tessa . </P> <P> When Brennan decided that she wanted to have a baby, she asked Booth if he would be the sperm donor . He agrees to Brennan's request at first, but subsequently struggles with the thought of not being involved in the life of his prospective child . Eventually he tells Brennan he cannot let her have his child if he is not allowed to be a father to it . Soon thereafter, it is discovered that he has a (benign) brain tumour . He has to undergo surgery, and though the surgery is successful, a poor reaction to anesthesia left him in a coma for several days . While in his coma, Brennan reads to him from her new novel, and he has an elaborate dream in which Brennan is his wife and that she is pregnant, and that the staff at the Jeffersonian play the characters in the novel . When he awakens, he initially suffers from amnesia, not recognizing Brennan . </P> <P> Although for the majority of the series Booth and Brennan denied that their relationship was anything more than friendly professionalism, they admitted to Dr. Sweets that they kissed and nearly spent the night together after their very first case together . After this discussion, Booth attempted to convince Brennan to give a relationship a try . However, she declined, telling him that she, unlike him, is not a gambler, and isn't able to take that kind of a chance . They have subsequently attempted to date other people, although the fact that Booth once comments that he regards Brennan as his "standard" for other women suggests that he, at least, has not completely moved on . Brennan does admit to her best friend Angela Montenegro that as time has gone on, she is unsure if she wants to keep doing consulting work for the FBI, citing that she is tired of murderers and victims, and is constantly worried that something will happen to Booth and she will be unable to save him . In the climax of Season Five, Brennan and Booth part ways for a year--he goes to Afghanistan while she leaves for the Maluku Islands in Indonesia--but they promise to meet, one year from that day, at the Lincoln Memorial . </P>

In what episode does booth and brennan get together