Antonin, Honoré and Papillote are sailors on the ship "L'Invincible". The three friends are in love with three pretty girls in Toulon: Honoré is in love with Mireille who, as for her, loves Antonin, and Papillote only has eyes for Angèle who, after a fifteen-month-long cruise,presents him a newborn baby that she claims is their son! A new woman appears: Patricia, as sexy as she is mysterious. Antonin, although disconcerted, falls under her spell. What he does not know is that Patricia is not a journalist as she says she is but a secret service agent who has been assigned the mission to investigate Eric Bergen, a shady fellow the trio meets everyday at Arsène's Café...