When a rash of suicides hits Cambridge University, DI Mark Joesbury recruits DC Lacey Flint to go undercover. The psychological histories, social networks, and online activities of the students involved share remarkable similarities. The London police believe that someone might be preying on lonely students and luring them to their deaths. If Lacey can play the role, she may be able to stop the killers. But is it just a role for her?