In 1959, after a group of nine student hikers are found dead in the Ural Mountains, KGB Major Oleg Kostin is sent to investigate. During the autopsy, Oleg has a flashback of a disturbing memory from WWII.

Oleg heads to Moscow to look further into the file of Alexander Zolotarev, the oldest member of the group, and makes a surprising discovery about his body.

Tempalov and the searchers examine the scene of the group's death, finding multiple confounding details that inspire different theories; Kostin shows his superiors a report that details strange objects in the sky, and a crucial discovery is made.

Kostin attempts get to closer the Dyatlov's case. He learns about the prison fugitives and attempts to find out whether this encounter was fatal for the tourists. Kostin decides to confess his feelings to Katya.