In the late 1960s, a serious crime occurred in a small town in the north: Ozersk. The cashiers working at the local timber enterprise were robbed and murdered, along with their driver. A large sum of money disappeared, and the cash-in-transit vehicle turned out to be submerged in a swamp. Investigator Sergey Penkin led an operations group to identify suspects. Everyone in town knows each other well, which makes it difficult for a criminal to hide unnoticed or flee with the stolen money. Presumably, the culprit is hiding in Ozersk, waiting for the right moment to escape. These suspicions were confirmed when a new crime took place—one that shook the calm townspeople.