René Sabin, engineer, disappointed by failures, leaves his village in the South to go to Paris with friends. In the capital, he befriends dubious people, in particular Alex Krakow who does not disdain shady business. Then comes the war. René is mobilized then returns to the country, and finds with joy his fiancée.
Adémaï is forcibly engaged to the farmer's daughter. He tries in vain to get rid of it and, weary of the struggle, flees in a plane with his comrade Michelet whom he believes to be an instructor. For three days and three nights, the unfortunates turn in a closed circuit, thus beating the world record.
"Taking its title from John Keats’s early 19th-century poem, this highly personal melodrama finds Dulac interrogating the archetype of the femme fatale. La belle dame sans merci follows a famous actress who was once seduced and abandoned by a rich man and subsequently resolved to become a “merciless woman,” forever scheming to hurt others (men in particular) in a ruthless yet captivating manner. Dulac challenges the Romantic archetype embodied in Keats’s poem by way of symbolist mise en scène, self-reflexive narration, and her typically associative approach to editing, locating a modern ambiguity within the stereotypical figures of 19th-century art." - Film Society of Lincoln Center