1812. Lieutenant Grigory Rylsky must deliver secret documents to Kutuzov. As soon as they reach the commander, the Russian army will begin its offensive. But on the way to headquarters, the lieutenant catches sight of a village girl and suddenly finds himself in the future, in the apartment of a young scientist, Dmitry Zhuravlev, and his wife, Katya, who are on the verge of divorce. While trying to return Gusar to the past, the time machine breaks down, and the lieutenant is forced to remain in the 21st century until the scientist repairs the machine.