In the midst of the epidemic, former criminal investigation operative Viktor Pugachev returns to his native Severoneftyansk, where the infection was known only from the news at that time. No one is happy for him here, because it is after his arrival that residents one by one begin to catch the coronavirus. The infection is spreading so fast that even the head of the criminal investigation department, David Yeghiazaryan, is ready to panic: the city is about to be quarantined, which means that the crime rate will rise sharply, and there is simply no one to fight it. The lieutenant colonel, in order to prepare for the worst-case scenario, gathers back his old department, which was dissolved five years ago due to the loss of important evidence. He can offer nothing but the certificates of the vigilante, nevertheless three out of four, including Pugachev, agree to work on these conditions, another promises to think about it. It quickly becomes clear to colleagues that the deadly epidemic is not the main reason why people in the city suddenly began to die more often than usual…