A mystery serial in six parts.
Dramatised for television by Giles Cooper from the novel by Eric Ambler.

Josef Vadassey was spending the last few days of his summer holidays for 1937 in the little Riviera town of St. Gatien when he was suddenly arrested on a charge of espionage. His accuser, Beghin, of the French Naval Intelligence, was inclined to believe he had caught a very incompetent spy but eventually he decided to force Vadassey to prove his innocence, and incidentally help the police, by questioning his fellow guests at the Hotel Reserve. Vadassey found this questioning slow work and what he hardly realised was that the spy soon knew that he was being watched. Vadassey, the hunter, was also to be hunted.