Theatrical institute student Tatyana Smirnova was killed, and her fellow student Nikita Rodin, who accompanied her home on the day of the murder, was seriously wounded. Loginov and Petrovskaya interrogate the young man and find out that on the eve of the tragedy Nikita was going to propose to Tatyana and was examining the wedding ring in a bar near their institute in front of two teenagers. Going out on the trail of the suspects, the investigators find the stolen ring and Tanya's handbag, but the teenagers deny everything and describe the attacker in detail.

Militiamen leave on an emergency call - robbery of the post office. When trying to detain, the robber explodes right in front of the guards. Loginov and Petrovskaya arrive at the scene. They are sure that the deceased Eduard Dorokhov had an accomplice who watched everything from the sidelines and had to turn off the timer upon successful completion of the operation. But finding out who could have forced Edward to do this dangerous business is not so easy.