The famous conductor Krechetov learns about the disappearance of his grandson Grisha. The case is being investigated by operatives Kosinsky, Lyudov, and Mezentseva.

Kosinsky suspects the boy's nanny, Mira, of being involved in the kidnapping. Mezentseva is attacked.

The investigators find out that Grisha is still alive. The Krechetov family receives a call from an unknown person demanding a ransom.