The body of high school student Joanna Walewska is discovered by three of her peers. Police initially believe that she may have committed suicide, but they soon find out there is more to the incident.

Police begin to interview students, under the supervision of their principal. They are joined by a psychologist, as they learn more about who Joanna really was.

Maciej remains in hospital, near death, watched by Ewelina and his father Jacek. Pawel makes a tempting offer to Sebastian, and the prosecutor asks for DNA samples from suspects.

Marta realises that the deed of sale for the property is partly fraudulent after examining it more closely. The police discover that some of the DNA samples were tampered with.

Joanna's mother opens up, which helps to clear one of the suspects of foul play. This leaves Pawel in a compromising position, as he was convinced of the suspect's guilt.

Lieutenant Kedzierski is alarmed by the surgical precision conducted in another recent murder. He realises he needs Pawel's help, and asks him to formally aid the police.