An American traveling in Europe suddenly disappears, and his daughter, married to an eminent scientist, receives a letter asking her to go to Antwerp, which she does with her young son. Both are about to disappear. OSS 117 is asked by his superiors to solve these mysterious disappearances.

The battle of the sexes as drawing room social satire. Philippe, a middle-aged newspaper editor, has lived for six years with Paulette, a successful stage actress. He tells her friend Claudine, a realistic and enterprising reporter, that he's thinking of proposing. Into the mix steps Carl Erickson, a charming Hollywood matinée idol in Paris briefly. He meets Paulette, sees her act (his box seat compliments of Philippe), and sets out to seduce her. The next two days bring talk, tears, separation, despair, surprises, and, perhaps, reconciliation as characters speak "exactly half the truth." It's a quadrille of changing partners.