When a respected and successful businessman claims that he is being blackmailed by Inspector Martineau, and provides evidence to support his allegations, the policeman's superiors have no choice but to suspend him from duty.

Martineau must go to work to clear his name, but the trail is a complex and dangerous one. The inspector has many enemies, not least Dixie Costello, whom he helped to put in jail and who is now once more at large. But is the trail a false one? And are all of Martineau's colleagues to be trusted?