The suicide of a famous professor gives the young officer the opportunity to marry the daughter of a retired state security major Smirnovskaya, move into her Moscow apartment and make his young wife Aglaya fall in love with him. However, family life turns out to be a difficult test. The mother-in-law has not lost her combat training skills and is always ready to practice them on her son-in-law, the beautiful wife is diagnosed with “mental retardation,” and in the professor’s house after his death, corpses appear, which the lieutenant has to get rid of. Finding himself drawn into a dirty scam involving missing accounts of former KGB officers, the lieutenant saves women from bandits and unravels the reason for the persistent surveillance of his mother-in-law’s apartment and the breaking into her safe.