Police captain Aleshin is investigating a case related to the theft of opium at a chemical factory warehouse. Everything suggests that the offender must be sought among the employees of the enterprise. One of the workers, Frolov, is familiar to Alyoshin in another matter. And although Aleshin is confident in Frolov’s honesty, he suspects something was wrong, seeing how he hides something from him and himself suffers from it. At the dacha, the factory director Vasiltsev killed his stepfather, who turned out to be an unnecessary witness. A trace brings Aleshin to a plant employee, a certain Olga ...