The Mountain of Light, in other words the Koh-i-noor of India is a beautiful diamond of great value which the Rajah of Punab wants at all costs. Right then, an American gambler Mr. Allan Poster, finds himself down the rajah's court. The rajak is convinced that Poster is just the man he needs and pretend-ing to be his friend, he organises any sort of parties, makes him get drunk and play innumerable games of poker till he takes on lots of debts. Then the rajah asks him to pay all his debts and threatens to kill him if he will refuse to do that. Luckily, Allan manages to escape. Then he meets a swindler, a fakir called Sitama, and they go together to Kiotna. Sitama tries to convince Allan to steal the Mountain of Light, which is on the forehead of the statue of the God Darmo Edja. Allan accepts to do it because of his pride. He makes a clev-er plan and succeeds in stealing the Mountain of Light. But Allan does not want to share out with Sitama and manages to seek off the fakir. But Sitama is extremely clever and finally he finds him. Allan is in deep troubles, but he manages to escape thanks to Lilamani, a bajadora. She helps him to hide him-self from Sitama and they go together towards the border of the English Pro-tectorate, where Allan will be safe. They get near the border, but Sitama and his followers reach them once again. They fight. Allan manages to escape, but Lilamani is token as a prisoner. Allan is in love with the girl, so he decides to give in to the fakir in order to save her. Sitama asks Allan to give him the dia-mond in exchange for their lives, but Allan does not trust the man and hes-itates. Suddenly, Sirdar the rajah appears and he explains everything to Allan. It was him who planned anything to make him steal the Mountain of Light. Sitama was only acting on his behalf. Thus, Allan gives the diamond to Sirdar. But Sirdar does not keep his promise and sentences him to death. Once again, Allan manages to escape thanks to Lilamani. Mad with rage, he sneaks into Sirdar's rooms. Threatening Sirdar with a gun, Allan forces him to give the diamond back to him. When Sirdar shows him the stone, Allan realises that it is only a reproduction of the Mountain of Light, which the fakir Sitama had swapped before disappearing. Allan runs after Sitama and finds him. Once more, he succeeds in faking away the diamond to Sitama. Then he goes to the pagoda of Kiotna and says that e has got the diamond. After saying that, he puts the Mountain of Light back to the God's forehead. Obviously, that stone was not the authentic one. Sirdar can't but accept his defeat, while Allan con finally go back home together with the beautiful Lilamani, after selling the splendid diamond to Queen Victoria.