Helping to investigate a series of killings, Detective Inspector Anna Travis accepts an offer of assistance from Cameron Welsh, a convicted murderer she helped arrest in the past, but Welsh's obsession with Anna brings terrible consequences.

Late night on a notorious high-rise estate in the borough of Hackney. A woman on the street never makes it home after a long night of drinking. A white van is being driven erratically. The driver is pulled over by the police and questioned. A suspect ... an arrest ... a confession. Case closed?