Alexei is transferred to a detachment controlled by Oleg. Now Alexey and Oleg are together, and no one can humiliate Alexei. In anticipation of the upcoming audit Kolosov tightens the regime in the "Lake". Mass searches and seizures of items prohibited for storage are carried out. During these events, a common fund of the third detachment falls into Kolosov’s hands. But at the request of Gosha Liver Kolosov returns part of the common fund. In addition, subordinates report to Kolosova on the success of Oleg sending letters to international human rights organizations. Kolosov still does not realize that this information is a "linden" transmitted to him according to Rokhlin's plan. Meanwhile, Ksenia, following her husband’s instructions, sends a book with the money hidden in it to Ozerny in the name of Alexei. Gradually, Oleg learns from Alexei the history of the laboratory after his voluntary exit from the project.