This spy business can happen to anyone. That's what William P. Nye discovers when he accepts the offer of a job from his friend George—just a casual invitation in a little Paris cafe. Nye little realises that this is the start of his meteoric careers as Special Agent X—an imaginary super-spy dreamed up as a ploy in the war of nerves... X bluffs and blunders along the perilous paths of big-time espionage—chained to the wall in a medieval torture chamber, snatched in the nick of time from the jaws of rusty iron pincers... jabbed by a red-faced enemy agent's knife on a crowded steamer... pea-shot with poison darts by a dwarf disguised as a schoolboy... chased by a gondola through the foul-smelling garbage-laden canals of Venice... flying an aeroplane without a lesson... duelling to the death with ancient battle-axes... Nye begins to wonder if he really is the indomitable, feared, king-size Agent X. Everyone else seems to think so...