The body of a young woman is found on a riverbank. She recently gave birth to a child. Chief Inspector Zawieja and her colleague Trepa investigate.

The police investigation continues, with new leads and evidence. Police are investigating a possible link between the murder and the debts and business dealings of Marcin Kosiński, the victim's husband.

Searching for new clues, Zawieja visits a psychiatric hospital where the victim used to work. She suspects that one of the patients could have contributed to her death. Meanwhile, Prosecutor Strzelecki receives a suspicious package.

Anka Janas is taken to the hospital. Meanwhile, the police launch the search for Wróbel, one of the victim's patients. Zawieja visits a prison in Goleniów where Wróbel was serving his sentence.

It's the day of the funeral of the murdered Magda Kosinska. The interrogation of an inmate at Goleniow prison points out new clues, and breeds new suspicions. The police secure the cemetery and wait for developments to unfold.

Prosecutor Strzelecki takes over the case. Zawieja doesn't give up and contrary to her chief's orders decides to follow his trail. The police decide to search tens of kilometers of tunnels under Szczecin.