Lesha Volchkov is an intern at the St. Petersburg criminal investigation team and, like any intern, dreams of solving the “crime of the century.” Seasoned investigator Sevidov reasons with the newcomer, but he digs the ground, especially since after the shootout of two city gangs there is a lot of work. The leaders of both gangs - European and Caucasian - are killed and, as the intern noted, one corpse is unnaturally cold, and the other is too hot. This is the guiding thread that the nimble newbie follows until he gets hit on the head. Now, perhaps, the solution to the “crime of the century” is not far away... In part, this work can be called a continuation of the story “The Dead Man Has No Claims” - the same characters, the same extravagant set of ways and means for the heroes to achieve their goal, the same unexpected turns plot in the finale. However, the story has a completely independent plot. The author's title of the story is “Protection Mechanism.”