Cassel is a seventeen year old boy from a family of curse workers, people with special powers. When he sleepwalks onto his school roof and is sent home, he becomes caught up in his brothers' plot to assassinate Mr. Zacharov, the head of a major crime family. Meanwhile, Cassel finds out that Zacharov's daughter Lila, the girl he thought he had killed, is actually still alive. She has been transformed into a cat, the same one Cassel has been dreaming about, and only Cassel can turn her back. Cassel learns the truth about himself, that he is a transformation worker but that his brother has been blocking his memories. He changes Lila back into a girl, and together they succeed in foiling the assassination of Mr. Zacharov.

While dreaming of a white cat, Cassel sleepwalks onto the roof of his boarding school and is sent home by the dean, who now considers him a liability. Cassel feels like he deserves this in some way, because when he was fourteen he killed the girl he loved, Lila Zacharov. He cannot remember murdering her, but he does remember standing over the body feeling gleeful.

Cassel is picked up from school by his older brother Philip and sent to stay with his grandfather at his mother's old house. She is currently in prison. There are stray cats in the barn, and Cassel brings the white cat inside. He dreams of the white cat again, this time telling him that only he can lift the curse on it.

The next day Cassel, who comes from a family of conmen, forges a medical note from a doctor in the hopes he will be allowed to go back to school.

All Cassel's family are curse-workers except for him, which makes him feel left out. One night he hears Philip, his other brother Barron, and Granddad, discussing him downstairs. He wants answers, so he tries to contact Barron. He goes to Barron's house and breaks in, where he finds footage of himself on the roof, with a white cat clearly present. He sees a note in Barron's diary saying that L is clearly there. There is also an animal cage in Barron's room that smells of cat. Suddenly Cassel thinks that Lila must be alive after all, and has been turned into the white cat. He thinks both brothers have something to do with this and that it was probably all ordered by Anton, who is Lila's cousin and wants her out of the way so he can inherit the family business.

However, when Cassel gets home, Philip has sent all the stray cats to an animal shelter. Cassel tries to get the Lila cat out but is told he has to be eighteen to adopt a cat. He asks his roommate Sam for help, and along with a girl called Daneca, they scam the animal shelter into giving Cassel the cat.

That night Granddad is drugged and Cassel is taken by his brothers and Anton to a restaurant. They want him to rehearse an assassination plan to kill Mr. Zacharov. Cassel realizes that his brother Barron is a memory worker who has been blocking Cassel's memories all this time, so that he will not remember he is being used to help them kill. Cassel is even more surprised to find out he is really a transformation worker and that Barron has been blocking this memory all his life. The only reason he is unaffected by Barron's powers now is that he has sewn memory charms into his leg. Cassel plays along with his brothers and Anton for now.

The next day Cassel turns Lila back into a person. They travel to Atlantic City where she is reunited with her father, Mr. Zacharov. She tells Cassel to go ahead with the assassination attempt but only pretend to turn her father's heart to stone. Cassel agrees. He confides in Sam and Daneca and tells them everything, then asks for their help. He is planning another con.

On Wednesday night he is picked up by Barron and Anton for the assassination. They go to the restaurant, where Daneca gives Cassel a fake blood pack Sam has made. Granddad spots Cassel and suspects something is going on. He tries to get Cassel to leave, but Cassel pretends he needs the bathroom. In the bathroom he pretends to kill Mr. Zacharov. Lila then comes in and pretends to shoot Cassel. Their plan works until Anton gets hold of the gun and realizes it is all faked. However, Barron is now on their side. He has experienced memory loss from the memory curses he has been using on Cassel, and keeps diaries to help him remember his plans. All Cassel had to do was change Barron's diary entries to make him think he is on Cassel's side. Barron holds the knife to Anton's throat, but Anton gets away and tries to kill Cassel. Granddad is forced to use a death curse on Anton. Mr. Zacharov thanks Cassel and promises not to harm his brothers if Cassel agrees to work for him now.

At the end of the story Lila tells Cassel that she has always loved him. Cassel is overjoyed until he finds out that his mother used her emotion work to manipulate Lila's feelings. Now Cassel can never be with her when he knows her feelings for him are fake.