Catherine Berlin, investigator with the Financial Services Agency, finds the almost-headless body of her informant 'Juliet Bravo', rolling in a shallow reach of the Thames. That Juliet Bravo's death is linked to an investigation of local loan shark Archie Doyle is no surprise to Berlin, but when Berlin's own unorthodox methods are blamed for the murder, she realises bigger predators are circling.

To start with, it looks as though Berlin will pay only with her job. And then, on a routine trip to her GP (one of a dying breed who will still prescribe heroin to long-term addicts) she stumbles across a second body.

Suspended, incriminated, and then blackmailed into cooperation by the detective leading the murder investigation, Catherine Berlin has seven stolen days of clarity within which to solve the crime - and find a new supplier.