Thérèse Ravenaz is a charming young woman but also the victim of a seducer who abandoned her as soon as he was told she was expecting a baby. To trace her unworthy lover, she boards a taxi driven by Emile Gauthier, a friendly cabdriver, who accepts to help her. But street after street, district after district, the seducer is nowhere to be found in Paris. And when she finally achieves the end of her quest, there is no Holy Grail. She learns the bastard is already married! Fortunately, Emile has a heart of gold...