A car crashes near a provincial English town. The badly injured driver is taken to a hospital where he dies, partly owing to a mistake made by a young resident doctor. The corpse, it turns out, was a con man, long wanted (and often caught) by the police, who are quite content to have him dead. But the error has placed the hapless young doctor's career in jeopardy, and two of his friends, a young surgeon and a journalist, set out to prove that his apparent mistake was actually the result of someone else's deliberate murder plot. Their suspicions become virtual certainties as the young men delve into the con man's murky past and discover many people who might have wished him dead. But trapping the murderer proves to be both a difficult and dangerous mission for the two nonprofessional investigators.