Sofia has a theory that the murderer has taken the law into his own hands and takes vengeance on people he blames. Surprisingly, the traces lead to Helsinki City Hall, where the mayor herself is in murderer's eyesight.

Mayor Tulisuo, who was abducted in the tunnel, is feared dead. Henna's smuggling operation ends in a surprising way. Sofia gets a message from beyond the grave that changes the direction of the murder investigation.