French actor Phillipe Martin (Lederer) enters a darkened movie theater to rendezvous with his married lover, Yvonne. However, Phillipe ends up mistakenly kissing a complete stranger, young and innocent Monique Pelerin (Lupino). The incident causes a furious media scandal, landing Phillipe in a zany screwball court trial, fighting against the Purity League as "The Kissing Monster." To protect Yvonne, Phillipe lies and states that he was overcome with Monique's beauty and could not resist kissing her, due to his romantic French nature. The charges are dropped, and Phillipe becomes an overnight celebrity and and the play he stars in a success. His testimony in court intrigues Monique, and leads to a burgeoning romance between Monique and Phillipe.