If people were given the ability to predict the course of events! .. Then Aida would not have gone on a date to the Aquarium Garden, then Manon, her sister, would not have agreed to meet her new admirer! And trouble would not have happened, and the private detective Alexei Kisanov would not have had to postpone the long-awaited vacation ... But the police ask for his help. Two brutal and mysterious murders. The disappearance of a girl drugged with a drug called truth serum. And, most importantly, the search for evidence of the guilt of the criminal, which is not given to the detective in any way! Will the killer go unpunished?