While investigating a poisoner at Edinburgh Zoo, Detective Inspector John Rebus sees a known paedophile photographing children. After a chase ending in the sea lion enclosure, Rebus decides to 'out' the man, in spite of assurances that he is trying to reform. As a campaign against the man starts, Rebus hears that the son of an ex-girlfriend has gone missing and starts investigating his disappearance from a nightclub with a mysterious blonde.

A convicted killer comes back from the U.S. having served his time in prison, with an agenda he wants to pursue. Rankin incorporated the novella Death Is Not the End as the missing person plot-line of this novel.