A medical congress in Paris that a suitcase mix-up turns into a terrifying nightmare... American cardiologist Richard Walker arrives in Paris with his wife Sondra for a medical congress. Before he can shave in the hotel bathroom, his wife disappears without a trace. The adventures that the brash man must undertake in a strange city place him between two groups seeking to obtain the switch to the atomic bomb and alongside the charming, non-conformist girl Michelle. She has smuggled the switch from the United States on a plane, but her and Sondra's luggage has been switched. Thus, an innocent married couple became involved in the whole case, around which the French police are circling helplessly and indifferently. While Walker's sole concern is to save his wife, the girl seeks a reward for her dangerous work...