Based on a true story, the film tells about the famous Soviet rocket launcher nicknamed “Katyusha”, which was kept in great secrecy during World War 2. One of these unique killing machines has drowned during an unexpected retreat of the Russian troops. A special unit formed of ex-athletes is sent to rescue the secret weapon that the Germans can never find — no matter what it takes…

Lyuba Solovyova becomes a witness to the accident, after which Pavel, unfamiliar to her, also Solovyov, ends up in intensive care. In the hands of Luba is his son Shura. Lyuba comes to the hospital, where she is mistaken for Paul’s wife. Unable to abandon a child who does not have a mother, and his father is in a coma, the woman decides to wait for Shura's grandmother to arrive from Germany, and for now, she assumes the role of wife and takes care of Pavel. Perhaps there are personal reasons for this: the whole situation unfolds against the backdrop of a break with her husband Sergei, who is sure that no one needs Lyuba, which means that you can behave with her as you like. And it is important for her to feel necessary - even if it is for an occasional person.