A group of crooks takes advantage of a rich old lady's naivete, they pretend they are to sail to Africa to fight the sleeping sickness. But in fact, they're only in it for the gold, they would get by trading the precious metal for trinkets.The honorable lady puts up the money for the trek. The raiders, Charlier, his secretary Genevieve and Leblond, just released from jail, set off on an expedition through the bush.