Juliette (Dita Parlo), a young woman living a montotonous existence in a village, marries Jean (Jean Dasté), a sailor working with the older and eccentric Père Jules (Michel Simon) and a cabin boy on the canal boat L'Atalante. The same day, she begins life on the boat. She at first is shocked by the lack of laundering, then by the cats that swarm around Jules, although she soon becomes fascinated by Jules's stories of his travels and the curiosities that he has picked up around the world over the years. She longs, though, to see the bright lights of Paris.
During an evening in the capital with Jean she becomes spellbound by the street pedlar and singer (Gilles Margaritas), and later leaves the boat to go off in search of him. Jean is disgusted when she doesn't return and tells Jules to cast off to Corbeil and leave her behind. Juliette realises how stupid she's been when she sees the missing boat, so she prepares to get a train ticket to Corbeil but has her purse stolen.
Meanwhile Jean too realises his huge error, particularly when he dives into the water and sees a vision of Juliette: his bride had told him that people see the person they truly love when they stare into water.* Worried for Jean, Jules returns to Paris and finds Juliette, hauls her across his shoulder in true he-man fashion, returns her to the boat, and the lovers are reunited. L'Atalante is considered as one of the greatest films in French – even in film tout court – history, and has influenced large numbers of film directors. Truffaut, for instance, used Jean Dasté in a cameo role as the doctor in L'Homme qui aimait les femmes.
*In some respects, the film is an amalgam of realistic images and dream-like sequences.