DI Chandler and DS Miles investigate the slaughter of four people at a tailor's fortified workshop. Ed Buchan, retained by Chandler as the team's historical adviser, believes that the huge archive at Whitechapel station will provide the necessary insight into this baffling crime.

The police drama set in London's East End continues with the second of a two-part story. A second mass murder occurs with no signs of an obvious break-in and no forensic evidence for Chandler and the team to use. The crimes begin to take on an almost supernatural edge and local residents wonder how they can sleep soundly in their beds when doors and locks offer no protection from whoever is responsible.

When traces of the aphrodisiac Spanish fly are found in murder victims, Chandler and Miles question what kind of killer they could be up against. The team are taken to the heart of a dark obsession where romance and love take on a sinister turn.

When a babysitter is murdered and a dangerous patient and former Whitechapel resident escapes from a psychiatric unit, the area is hit by a series of terrifying events. Fearing that a spree killer is on the loose, Chandler, Miles and the team must act fast to prevent more deaths. Meanwhile, Chandler's quest to bring in a suspect alive jeopardises his relationship with Miles.

The masked killer is still at large, and Chandler is particularly interested in a woman who managed to survive an attack. He and Miles must resolve their differences to bring the killer to book.