Jenny es una chica pizpireta que, cuando viaja a París, se escapa y conoce a un chico al que toma por un gangster, aunque no lo es. Sus aventuras terminarán bien.

Penny est une charmante jeune fille romanesque mais ayant du caractère, que sa mère a mise en pension. Lors d'un voyage à Paris, elle s'échappe et rencontre Antoine qu'elle voit comme un jeune gangster, ce qu'il n'est pas. Ce quiproquo leur vaudra des aventures qui heureusement finiront bien...

Penelope Benson, known as Penny, is both romantic and determined. Put in a select boarding school by her mother, she takes advantage of a trip to Paris to get away from it all and live her own life. That's how she meets Antoine du Merlet, whom she takes for a young hoodlum when in fact he's a police superintendent. She spends the night at his place, which leads to a number of setbacks for poor Antoine, who is stigmatized by the headmistress, abandoned by his mistress and has to face a strip-tease session starring the unconscious Penny... But Penny's a spicy one and Antoine's a nice guy, so... !