 When she sets sail for Lisbon, Catherine Laurence, a famous classical singer has but one wish: to be left alone. Unfortunately she soon gets bothered by a rude, invading man. Later she gets to know him better and becomes susceptible to his charm. She realizes that Michel is in love with her and it is not long before she goes beyond her disastrous first impression. Although not quite sure he is a perfectly honest man she entrusts him with a delicate assignment: keep her precious pearl necklace coveted by Van Coolart, a fake Dutch diamond-merchant, and give it back to her in Paris. If he is a robber himself, so much the worse for her. But if Michel keeps the Paris rendezvous love is in store for both of them. Nevertheless there is a crucial factor she regrettably disregards, composer Raymond Aubour, a faithful friend who has been her suitor for ten years...