A seemingly ordinary passenger train is rushing across the Russian expanses, but in fact it is a disguised strategic missile system. Playing a large role in the parity of the leading nuclear powers of the globe, the complex turns into a trump card in world politics, after which it becomes an object of espionage and a target of sabotage and terrorist activities. A graduate of the rocket school, Lieutenant Kudasov receives assignment to this extremely important facility and finds himself in the center of confusing and dangerous events, as well as love affairs. Unique mathematical abilities, a stable nervous system and human decency help him emerge victorious from difficult life conflicts, save his life and save the world from nuclear war.