Having recently moved into her new apartment, Irène Cazenave, the widow of a well-known police officer, is forced by one of her husband's colleagues to take part in an investigation. The building's provocative concierge has been found murdered. We watch a parade of suspects, only to learn at the end that Irène killed the janitor under blackmail. She kills herself.

André Courvalin, a merry bachelor, considers marrying, but not his exuberant mistress Aurélie. He would much rather wed sweet Suzanne. Trouble is that Suzanne is already engaged to Yves, one of his friends. But every problem has its solution. Accordingly, André finalizes a cynical stratagem. He sends Yves to negotiate his own breakup with Aurélie while he warns Aurélie's husband about Yves' presence by her side.All goes according to plan : Yves is mistakenly taken for Aurélie's husband.