Having left the Missouri town of Wind Gap for the windy city of Chicago, young journalist Camille Preaker is working for a local newspaper but not enjoying it particularly because she sees the worst of human life. She has survived an unpleasant childhood, but the death of her younger sister as a child has left her with significant post traumatic stress disorder and she has a history of self-harm. Camille gets along well with her Editor-in-Chief, Curry, who cares about her in a fatherly kind of way, and gives her an assignment he thinks might help her come to terms with her past; a young girl has gone missing in Wind Gap.
Camille arrives in Wind Gap shortly after the little girl, Ann Nash, is discovered dead, and another, Natalie Keane, has gone missing. The Nash family tell her that the police believe the killer to be a local man and originally they considered her brother a person of interest, but his alibi was validated and they began to follow other leads. It becomes clear that a serial killer is at work in Wind Gap when Natalie's body is found in the same condition that Ann's had been. Both girls have had their teeth pulled, and both were strangled. Camille starts to write her story for the paper but Curry suggests that she stay to follow the enquiry.
A surprising benefit of returning to Wind Gap is that Camille is able to reconnect with her estranged mother, Adora, one of the wealthiest and most socially respected women in town. Camille's half sister, Amma, is the town's mean girl; she is also the most popular girl in town, and rules the roost amongst her peers. She is spoiled and pampered, and is also a skilled manipulator. She puts up a facade in front of her parents; she pretends to be younger than her years so that they will not realize that she is secretly drinking.
A detective from Kansas City is brought in to investigate the murders, and because they spend a lot of time together talking about the crimes, Camille and Richard Willis begin a relationship. Willis expresses his feelings for Camille, but she will not let him see her naked because of her scars that are all over her body, and that she knows will shock and repell him.
When Camille and Amma go out drinking one night, Camille gets drunk and goes to bed, feeling unwell. When she wakes up she finds that Amma is medicating her will pills and is stunned to find out that this is how Adora medicates her daughter. She realizes that her little sister Marian was probably not sick at all and that her illnesses were always caused by their mother. Camille suspects that Adora suffers from Munchausen's Syndrome by proxy, and when she reads through some notes that the nurses who treated Marian had written, she finds that they also believed that Adora was killing her daughter. Camille shares her suspicions with Willis. He agrees with her and confides that he also suspects her of killing Ann and Natalie as well. He is working on gathering enough evidence to arrest her.
Things take a dangerous turn when Adora starts trying to poison Camille whilst she is at her house. She then bathes her, tries to give her medication and starts to bathe her old scars and wounds. Camille lapses in and out of consciousness but when she wakens she sees her mother being arrested, and Willis standing over her naked body with a look of horror on his face. Despite his declarations of love, he is repelled and horrified by the way in which she has cut herself and he ends their relationship.
Amma is ordered to move to Chicago to live with Camille. Things seem to be going well to start with; Amma seems to be working through the shock of her mother being arrested for murder, and she starts to attend a local girls' school where she seems to be doing well. Shortly after she starts at the school one of her classmates disappears. Her body is soon discovered; she has been strangled and has had several teeth pulled. Although Adora had killed Marian, she had not been the killer of the little girls; Amma had murdered Ann and Natalie.
This is too much for Camille to process. She starts to cut herself again but Curry picks up on this and he and his wife invite her into their family where they begin to treat her as their daughter. It is the first time that Camille has been treated like a child should be treated, and it takes her some time to get used to it.
