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.