The ladykiller friend of a busy diplomatic attaché follows a masked blonde home after an elaborate ball without knowing she is that man's wife.

Director Rosé and his opera company travel to Monte Carlo where they expect an engagément to perform at the opera house. During the boat trip Mario, the cheerful tenor, meets a girl hidden in his cabin. He helps her singing for her passage and soon Nicole is adopted by the whole troupe. Then at Monte Carlo the opera director has no intention to sign them. But he has an eye for beautiful women, so Nicole will try to persuade him to reconsider the offer.