Twenty-five-year-old Lucile is the beautiful mistress to Charles, a wealthy, kind-hearted businessman who provides for all her material needs, but for whom she has no true love.

When she meets a charming young man her own age, Antoine, she falls in love.

But Charles helps her through her crisis by funding her abortion – against the wishes of Antoine, who nevertheless accepts, even though he planned on moving out of his bachelor flat, the three of them into a soulless concrete block, money being short.

In his review in The New York Times, Vincent Canby wrote, "Cavalier may have created a practically perfect screen equivalent of the novelist's prose style.

"[4] In addition to praising the performances by Deneuve and Piccoli, Canby writes: La Chamade (literally "the heartbeat") is a movie of technical skill and pure images that capture the textures of things—whitewashed walls, a piece of modern sculpture, cut flowers, flesh tanned in the sun—all of which give reality to a narrative line from which everything nonessential to the affairs of the heart has been refined.