When a Cambridge student dramatically attempts to take her own life, DI Mark Joesbury realizes that the university has developed an unhealthy record of young people committing suicide in extraordinary ways. Against huge personal misgivings, Joesbury sends young policewoman DC Lacey Flint to Cambridge, with a brief to work under-cover, posing as a depression-prone, vulnerable student. Psychiatrist Evi Oliver is the only person in Cambridge who knows who Lacey really is - or so they both hope. But as the two women dig deeper into the darker side of university life, they discover a terrifying trend. And when Lacey starts experiencing the same disturbing nightmares reported by the dead girls, she knows that she is next.