The premise of the book is that the protagonist and an otherworldly being try to figure out who in the community is a "monster," the in-universe term for a sexual predator, in order to bring him to justice. The monster turns out to be the protagonist's friend's uncle. The uncle had been molesting the friend's younger brother. There are no specific descriptions of what the uncle was doing to the child. The uncle makes several gaslighting statements when his actions are revealed.