The man who lies bleeding to death in a London brickyard is no ordinary drifter but a secret informant prepared to divulge details of a potentially devastating international plot against the British government. Special Branch officer Thomas Pitt, hastening to rendezvous with him, arrives a second too late, preceded by a knife-wielding assassin. As the mortally wounded man’s life slips away, so too does the information Pitt desperately needs. The killer in turn flees on an erratic course that leads Pitt in wild pursuit, from London’s cobblestone streets to picturesque St. Malo on the French coast. Meanwhile, Pitt’s supervisor, the formidable Victor Narraway, finds himself accused of embezzling government funds. With Pitt incommunicado in France, Narraway turns to Pitt’s clever wife, Charlotte, for help.