An ordinary-looking passenger train races across Russia’s vast expanses—but in reality it is a disguised strategic missile complex. Playing a major role in the balance of the leading nuclear powers of the world, the complex turns into a trump card of world politics, after which it becomes an object of espionage and a target of sabotage and terrorist activities. A graduate of a missile academy, Lieutenant Kudasov is assigned to this super-important facility and finds himself at the center of tangled and dangerous events—as well as romantic escapades. Unique mathematical abilities, a stable nervous system, and decency help him come out the winner from complicated life clashes, keep his life, and save the world from nuclear war.