Upon his successful invasion of Baghdad, Hulagu Khan, the Mongol ruler, orders that one hundred of the city's citizens be tortured to death until the Caliph, the deposed ruler of the city, is turned over to him. Outside the city, the Caliph attempts to organize his troops and retake Baghdad while his young son Ali hides in the home of Prince Cassim. Cassim, however, is a traitor to his people, and the Caliph falls into a Mongol trap and is killed. Ali manages to escape, however, and as he wanders the barren lands outside the city, he discovers a secret cave which is home to a band of thieves. Upon the thieves' return, the brave Ali is accepted into their ranks and adopted by Old Baba, their leader. Ten years later, the thieves are the only remaining resistance in Baghdad to the rule of Hulagu, who offers 10,000 pieces of gold for the capture of their young leader, Ali Baba, and the destruction of his men. Learning about a Mongol caravan carrying the fiancée of Hulagu, Ali and his protector Abdullah ride to investigate the matter, and Ali is captured as he talks to Amara, Cassim's daughter and Hulagu's intended. Upon her arrival in Baghdad, Amara tries to break her engagement to the Mongol leader, but the ambitious Cassim forbids it. Later, as he is being prepared for torture, Ali recognizes Cassim, and the young man vows to avenge his father's death. Upon the urgings of Jamiel, her slave, Amara attempts to tell Ali that she is not responsible for his imprisonment, only to be taken prisoner herself when the thieves rescue Ali. Old Baba is mortally wounded in the rescue, and his dying wish is that his adopted son reclaim his rightful place as the ruler of Baghdad. Unaware of Amara's heritage, Ali arranges to trade her for Cassim, but upon their arrival at the traitor's estate, Ali realizes that she is his old childhood friend. Meanwhile, Hulagu receives Ali's offer and tells Cassim that the choice is his. When the cowardly traitor does not appear at his home the next morning, the thieves call for Amara's death to avenge that of Old Baba, but Ali refuses and orders her safe return to Baghdad. When Amara arrives at Hulagu's palace, Cassim confesses that Ali is the Caliph's son, after which Amara proclaims her love for the bandit leader. Amara is then tricked into agreeing to marry Hulagu when Cassim pretends he is being tortured. The wedding, however, is merely another Mongol trap for Ali and his men. Despite Cassim's preparations, Ali and his men manage to overwhelm the Mongol troops and gain entrance into the city. Failing to uncover the thieves, Cassim is executed by Hulagu. Soon thereafter, the thieves attack, and with the help of the people of Baghdad, the Mongols are defeated. Ali then takes his rightful place as the new Caliph, with Amara at his side.
