Pursued by a rival gang after a violent robbery, Toni escapes with nearly thirty million francs. On the train to Paris, to avoid arousing suspicion, he has no choice but to threaten an honorable philosophy professor, Justin Mignonnet, with his gun, so that he will carry the loot for him. To make sure he returns the money, he takes his papers and makes him promise to be present at the exchange appointment at the Pigalle Hotel the next day. Completely lost, Mignonnet decides to obey orders, but just as he is about to return the money, a young woman, a member of the enemy gang, comes to collect it.