The story begins at the airport and on an international express train, which is being carried by a German citizen, Otto Lang. The conductor and his girlfriend are solving the problem of living together, and it seems that the conductor has come into a lot of money. In the evening, a fight breaks out between two young men in a nearby pub. The next day, the body of one of them is found near the track. However, the investigators come across another body in the forest, this time that of an unknown man. They try to find out his identity and the relationship between the dead. They start questioning the people who were on duty on the express train that night. They also come across several hotel scammers. Then another clue appears – heroin found on another German citizen. With each new fact, the search seems more difficult...