Kalgan joins the tenth squad, led by a powerful prisoner known as Mongol and his gang, the "blacks," who dominate the colony's hierarchy.
Initially enduring brutal punishments, including a stint in solitary confinement, Kalgan eventually earns respect among inmates, who recognize his unyielding character.
As he navigates the dangerous social dynamics, Kalgan receives an offer to become a foreman for the work squad, allowing him to avoid grueling labor.
Tensions reach a peak as Philatelist criticizes the work quotas that privilege the "blacks" and rejects their domination, leading the squad into a strike that alarms the prison administration.
The "blacks," wary of Philatelist's growing influence, conspire to discredit him, and he is brutally assaulted after being accused of colluding with the authorities.