En route by boat to a deplorable prison in Cayenne, the convicts are in distress, for they leader, Chéri-Bibi is rumored dead. Everyone is looking for him, the other inmates, the on-board police, and even a nun. But what has become of him?
Having taken over the ship, Chéri-Bibi explains to the commandant-turned-prisoner how he was framed for a murder committed by the man in the gray hat. Shipwrecked, Marquis du Touchet and passengers arrive on-board Chéri-Bibi's L'Estrella.