<P> One day, Rachel is stunned to see Megan kissing a man other than her husband . The next day, after a night of heavy drinking, Rachel awakens to find herself bloody and injured, with no memories of the night before but certain that she has done something she will regret . Soon, she learns that one of the top stories of the day is that Megan is missing . Rachel is questioned by the police after Anna reports having seen her staggering around drunk in the area the night of Megan's disappearance . Rachel starts to become interested in the missing persons case . She contacts the police to tell them she thinks Megan was having an affair, because she was watching her every morning and evening from the train, and then she contacts Megan's husband, Scott . Rachel lies and tells Scott she and Megan were friends, and she tells him her thoughts about the affair . Rachel learns that the man she saw kissing Megan the day she disappeared was Kamal . </P> <P> Rachel contacts Kamal, lying about her true identity and background as part of a ruse to get close to him and learn more about him . She makes a therapy appointment with him, ostensibly to see if he can help her to recall the events that happened during her blackout the night of the disappearance . While Kamal suspects nothing, Rachel begins to gain insights into her life by speaking with him, inadvertently benefiting from her therapy . Her connections to Scott and Kamal, though built on lies, make her feel more important . She ends up not drinking for several days at a time but always relapses . Meanwhile, she continues to call, visit, and harass Tom and his new family . Then Megan's body is found; she is revealed to have been pregnant, and her unborn child was fathered by neither Scott nor Kamal . As Scott discovers Rachel's lies and lashes out at her, her memories of the night of the incident become clearer . Rachel remembers seeing Megan get into Tom's car . At the same time, Anna discovers that Tom and Megan were having an affair . </P> <P> These associations enable Rachel to trust her own memories more, and she realises that many of the crazy things Tom told her she did while drunk, but that she doesn't remember doing, never really happened . He had been gaslighting her for years, which affected her belief in herself and made her question her sanity . Armed with this sad realisation, and the knowledge that he must have been the one who killed Megan, Rachel warns Anna . When Anna confronts him, Tom confesses to murdering Megan after she threatened to reveal that he had impregnated her . Anna is cowed, fearful for her daughter's safety . Although Tom tries to beat and intimidate Rachel into keeping silent, she defies him and fights back . Knowing he is about to kill her, Rachel stabs Tom in the neck with a corkscrew . Anna helps Rachel make sure that he dies from the wound . When the police arrive, former adversaries Rachel and Anna co-ordinate their stories to support their actions having been in self - defence . </P> <P> The Girl on the Train received mostly positive reviews from critics and audiences alike . In 2015 it became the fastest - selling adult hardcover novel in history, and it spent over four months on the New York Times Bestseller List following its release . Kirkus Reviews praised the novel with a starred review, writing that "even the most astute readers will be in for a shock as Hawkins slowly unspools the facts, exposing the harsh realities of love and obsession's inescapable links to violence ." Subsequently, the novel was honoured by Kirkus Reviews as one of the best books of 2015, in the fiction category . The book also won the 2015 Goodreads Choice Award in the category Mystery & Thriller . </P>

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