Juliette Hardy is sexual dynamite, and has the men of a French coastal town panting. But Antoine, the only man who affects her likewise, wouldn't dream of settling down with a woman his friends consider the town tramp.

Fred Barker, an unmarried American who remained in France after heroically defending the country during the Second World War, runs the perfume factory in Grasse of his friend Carlo Ferelli, whose life he saved during the conflict. Fred has since adopted a little girl, Cathy. One day, he receives a visit from Félix Mercier, an old man who informs him that he has taken Cathy into his custody and that he will return her to him when Fred finds his granddaughter Hélène, a 17-year-old teenager who accuses the factory of being a front for white slavery. Fred, dumbfounded, sets out to find Hélène, so he can quickly get Cathy back.

Professor Charles Buisson, astronomer and Nobel Prize winner, has just discovered a nova. He informs the other observatories by telephone. Just as he thinks one of them is calling back, he finds himself on the line with a young woman threatening suicide at the Ruban Bleu cabaret, if her lover hasn't joined her by midnight. Intrigued, the professor decides to go and prevent the unfortunate woman from committing suicide. One of his students, who earns her living as an understudy in a knife act, helps him in his investigation, while the school principal and a policeman suspect him of being a prankster or even of selling drugs. For the scientist, it's an opportunity to discover a world of music-hall that he'd never known before: "I thought I knew the sky chart by heart, but there's one planet that was totally unknown to me: Earth. I'll be back!