When a rash of suicides tears through Cambridge University, DI Mark Joesbury recruits DC Lacey Flint to go undercover as a student to investigate. Although each student's death appears to be a suicide, the psychological histories, social networks, and online activities of the students involved share remarkable similarities, and the London police are not convinced that the victims acted alone. They believe that someone might be preying on lonely and insecure students and either encouraging them to take their own lives or actually luring them to their deaths. As long as Lacey can play the role of a vulnerable young woman, she may be able to stop these deaths, but is it just a role for her? With her fragile past, is she drawing out the killers, or is she herself being drawn into a deadly game where she's a perfect victim?