In 1918, security officer Yegor Sidorchuk, on behalf of his superiors, handed over a box of diamonds for safekeeping to the Red commander Nikolai Postnov, his friend and comrade in arms. Then Sidorchuk was caught up in the whirlwind of the Civil War: he took part in battles with the White Guards, suppressed kulak revolts and did not remember the story with diamonds. Until one fine moment he was urgently called to the Lubyanka and asked to find Postnov. The fact is that the red commander escaped, taking jewelry with him. He betrayed his homeland. And Sidorchuk must find and punish the traitor. Find and punish your friend...