Léontine, an old baroness, opposes her granddaughter's wedding for moral reasons. But Adolphe, her first husband reminds her that her own conduct in the past was far from irreproachable. Didn't she cheat on him ? And after her divorce from him and her remarriage with a baron, didn't she do the same thing to her second husband? Léontine then realizes she is in no position to lecture her granddaughter, all the more as she loves her fiancé truly...