During World War II, R.S.M. Wilson runs a British military stockade in North Africa with an iron hand.  To break down the spirit of five new prisoners, Wilson directs Sergeant Williams, a sadistic new guard, to walk the men up and down a large man-made hill of rocks and sand with full packs on their backs until they drop from exhaustion.

Jacko King, a Jamaican Negro arrested for stealing three quarts of Scotch from the officers' mess, receives especially harsh treatment because of the prejudice of the guards.  He supports prisoner Joe Roberts, a warrant officer broken of his rank for striking a superior officer and refusing to lead his forces into battle when their ammunition was low, in his revolt against the cruel actions of the guards.

When the weakest prisoner, George Stevens, guilty of going AWOL to return to his wife, dies, the prisoners threaten to revolt.  At first, Stevens' death is officially recorded as an accident, but Roberts persuades the medical officer to testify to the inhumane conditions in the stockade in hopes that conditions for future military prisoners will improve.  The rest of the group only want revenge against Williams; and in killing the guard they lose their opportunity to put an end to the brutal system.