On the evening of April 6, businessman Mikhail Melnikov was killed on the threshold of his house. The investigation has reached a dead end. A friend of the deceased, Airat Khakimov, advises Mikhail’s relatives to contact a private detective from Rostov-on-Don, N.F. Trubnikov. Trubnikov gives in to persuasion and agrees to conduct an investigation online. However, the situation is complicated by the fact that the detective himself is in the hospital, he is confirmed to have coronavirus. Nevertheless, he was able to find the killer of the Moscow businessman.