At night, a young promising scientist is killed in the laboratory building of a pharmaceutical company. The “homicide department” of the Moscow Criminal Investigation Department begins to deal with this murder, and in parallel with it, Turetsky and Pletnev are conducting their own investigation. Almost all employees of the company who worked under the program of the newest immunostimulant fall under suspicion. During the autopsy of the deceased, it turns out that he died not from a blow to the head, but from the effects of some drug that was slipped into his cognac. Who needed this death and why?