Mr Jo, dubbed "the man with the Buick," is the town's darling. However, he is a trafficker with a bad reputation who wishes to forget his past and is now limiting himself to smuggling rubies under the guise of a charitable organization that offers underprivileged children vacations in Switzerland. Mr. Jo, on the other hand, is in love with a lovely widow and is willing to get involved in another hold-up in order to marry her. And "the man with the Buick," who seemed so honorable, will surprise the people of Honfleur when Inspector Menard reveals his secret activities.