According to the novel of the same name by Tatiana Ustinova.

Young Maria Veprentseva is the secretary-referent of the well-known detective writer Dmitry Rodionov. The girl diligently performs her duties and knows all the habits of the employer. Maria is also raising her 13-year-old son Sylvester. Dmytro has to go on a business trip to Kyiv. Book publisher Markov does not want Rodionov to go to the Ukrainian capital. There, the writer must meet with the influential Boris Golovko, who intends to offer an extraordinary fee for the right to screen his works. In addition, Markov is affected by the fact that Dmitry always denied him such a case.

Tatiana is also preparing to fly to Kyiv. Suddenly she begins to receive threats. An unknown person hints that if Dmytro flies, her son will suffer. Soon a sister, with whom she had not seen for 9 years, appears on the doorstep of the secretary's apartment. In the past, a relative suffered from drug addiction. Now she asks Maria to help her out by giving her a large sum of money. Veprentseva doesn't have that much money, but her sister threatens to tell Sylvester the truth that his mother so carefully hides. Upon learning about the assistant's problem, Dmytro goes to meet him and persuades her to take her son with him to Kyiv. The writer is sure that the threats came from his sister Maria, and now everything will be fine ...