Professor Branck invented Fortuna a machine providing absolute luck, fortune and success, to whoever uses it, provided they are a virgin. Trying the experiment, Lucien Lepur, a street vendor who has never known a woman before, becomes the man of all successes. But he soon regrets Micheline his fiancée and finds himself under the influence of Professor Branck. Helped by Casimir, Micheline snatches Lucien from Professor Branck. Falling into her arms, Lucien loses all his powers but wins love.