DI David Vogel is first on the scene when Melanie Cooke's bruised and strangled body is discovered in Bristol's red-light district. The evidence points to Melanie's father being the killer, but Vogel's on edge. The quick arrest is too easy, too straightforward.

When two new murders are reported, Vogel's team broaden the search: new evidence suggests that there are three different, disturbed criminals. Any one of them could have killed Melanie, but which one did? Vogel's team inch towards the answer, never suspecting that the killer is watching them too, waiting for his moment to strike.