Ali Baba discovers a cave full of treasure guarded by 40 thieves in the forest. His brother-in-law, Kasim, goes to the cave to steal the treasure but gets locked inside and killed by the thieves. His wife dies of grief and Ali Baba takes in Kasim's maid, Morgiana, as his own. When the 40 thieves come to the village to find out who knows their secret, Morgiana outsmarts them by marking all the houses with the same mark. The thief leader disguises himself as an oil merchant and goes to Ali Baba's house, but Morgiana saves them by pouring hot oil into barrels and creating a barricade. Ali Baba is grateful and makes Morgiana a part of the family, being the only one who knows the secret of the treasure cave.