Banker Jules Coupeau is travelling to France on a luxury liner, carrying a diamond necklace of immeasurable value. He befriends a detective who is travelling with him, and they check into the Hotel Cosmopolite in Marseilles. There, the notorious criminal Badinguet, an Apache, plans to steal the jewellery. With the help of his lover Gervaise, he tries to lure the detective out of town. At first, the detective falls in love with Gervaise. But then he realises what could happen and travels back to Marseille to help the banker. In a fight to the death, Gervaise throws himself in front of the detective and is fatally shot. The detective wins the ensuing duel.
