A town the size of Castlemere might expect to see one major fire a year. When a derelict warehouse burns down just days after a blaze destroys Rachid's Eight-Till-Late, Detective Chief Inspector Frank Shapiro is worried. Either of the fires could have been accidental, but together they suggest an arsonist at work. A third, and fatal, episode confirms it.

Helped by his enigmatic Irish sergeant, Cal Donovan, Shapiro investigates, well aware that any delay in making an arrest will invite further attacks. But before much progress can be made Shapiro is relieved of duty, accused of destroying vital evidence in an earlier investigation - evidence that would have spared an innocent man an eight-year prison sentence.

Shapiro's closest colleagues, Detective Inspector Liz Graham and Detective Sergeant Donovan, are incredulous: the allegation wars with everything they know about a man they have worked for and respected for years. And yet the evidence can't be ignored.

Liz and Donovan must embark on a race against time to clear Shapiro's name - if they can - and to track down a pyromaniac before he brings his career to a truly horrifying climax.