Grégoire Vachette is a bashful librarian, forced to listen to the daily boasting of his colleague Courgéan, a great seducer according to what he says. But when, while on holiday, Grégoire meets beautiful Madeleine, the shy young man becomes fired up. Back to his place of work, he can't help communicating his enthusiasm for Madeleine, so much so that he too is taken for a Don Juan. But Madeleine is not for him. Nevertheless, his unexpected change of attitude will have helped him to conquer the heart of Denise, a typist who loved him in secret.
