Set in Venice, this espionage thriller concerns a gang of saboteurs who've been targeting French military installations. Gallic secret service agent Cyril (Jean Pierre Aumont) is sent to investigate. His progress is impeded by worldly-wise cabaret singer Katherine (Carla del Poggio), who may or may not be involved with the saboteurs. During most of the film, action and adventure take a back seat to the Aumont-del Poggio romance, which plays itself out against several photogenic Venetian locales. Things begin picking up again in the last reels, culminating in a thrilling denouement.

Source : allmovie.com