A serial killer murders wealthy businessmen. He lures them to his sprawling estate under the pretext of selling it. However, one of the murders does not fit into this series, even though it is similar to the others to a certain extent. The widow of businessman Sojková is also a suspect, but she is also acting as an amateur detective. She searches for her husband's killer on her own, as she believes the incompetent police are unable to catch him.