Nils Olaf Chrisander

The noble family de la Porte lives at castle Medan. After the lost heir August returns unexpectedly, countess Herm, mother-in-law of younger brother Johann, fears for the inheritance of her daughter.

In Calcutta, McAllan meets the beautiful Indian woman Malatti, with whom he immediately falls in love. The engineer quickly neglects his professional obligations and follows her. After some complications, the two of them finally get closer at her home, even if Malatti's father Badhama rejects this connection. Badhama only agrees to the planned marriage when he learns how wealthy this white man must be. After some time, McAllan returns to his large construction site, where things are going haywire. Many workers die in an explosion, and McAllan is now liable with his fortune. As a result, the engineer, who became impoverished overnight, suddenly becomes uninteresting for Malatti's father as a son-in-law, especially since with a solvent Japanese man who offers a lot of money for his daughter's hand,

The American engineer McAllan is appointed site manager for a major project in Asia. He is to oversee the branch line of the railway line from Calcutta to Beijing. One day, the railway company in question called him to Calcutta for an interview: they were planning to stop running the branch line for cost reasons. However, McAllan is passionate about the project and uses all his powers of persuasion not to just call off construction. In fact, the construction work will continue, and the engineer is even willing to vouch for it with his private fortune.

Count de Faber is working on a new type of explosive, but finds out that Professor Plussman has beat him to it. After an unsuccessful attempt to acquire the formula from Plussman, he breaks into the professor's house, steals the formula, and kidnaps his daughter, Mary. He takes her to Carlsten Fortress.

To escape an arranged marriage, a young Italian girl marries an older man, a military officer who is also a family friend, and when he is assigned to North Africa, she accompanies him. His unit is sent into the desert to subdue some unruly tribes, and when he is later reported killed in action, his widow marries a young soldier with whom she has fallen in love. However, word soon comes back that her "dead" husband is very much alive.

Malatti's father has unexpectedly survived the fall from the train and now vows to take cruel revenge on McAllan. In Lhasa, the old capital of Tibet, seat of the Dalai Lama and at the same time a "forbidden city" for all foreigners, there is another dramatic encounter between the engineer and Badhama. In a dark dungeon, he thinks he recognizes McAllan and tries to stab the man he holds responsible for all the misfortune. He does not realize who he is stabbing, killing his own daughter in the process. The Dalai Lama's servants arrest Badhama and throw him in the dungeon. Malatti's father is sentenced to death, while McAllan sees the light of day again and is released.