The city's medical community is in panic - someone is kidnapping doctors and nurses and giving them a lethal injection! The medical investigation department, where doctor Agniya Smolskaya works, found out that the murdered medical workers made a medical error that killed the patient, and got away unscathed. It also became known that all the victims, shortly before their deaths, received anonymous letters that spoke of the inevitability of retribution... Quite by accident, Agnia discovered a similar letter from her husband, surgeon Oleg Shilov. Recently, his patient died during an operation, but this is not Shilov’s fault... We urgently need to find the unknown avenger before the killer gets to his husband!