During a cruise for high school graduates organized by Belfr and his father, called the Captain, one of the students, Kacper Krynicki, disappears. Shortly afterwards, the police find the boy's body on the beach.

The police determine the identity of the boy found on the beach. The investigation is led by Assistant Commissioner Ewa Krawiec. The teacher begins to suspect that the Captain is hiding something from him.

A recording appears on the Internet which shows that Kacper most likely committed suicide. Meanwhile, the newspaper publishes an article accusing the Captain of violence against students.

Belfer finds a recording in the Captain's house that casts suspicion on Krynicki.

Belfer suspects that Kacper was the Captain's son. The tailor and Drużbacki find traces of blood in the warehouses. One of the employees confesses to the murder.

Belfer gives the police the recording of Ivan's death. Kacper decides to confront his father.

Butryś kidnaps one of the students. However, thanks to Belfr, he manages to rescue him. Belfer finds out who is behind the Captain's death.