With its 3649 lines, The Castle of Perseverance is of interest as an exhaustive compendium of such morality features as the battle between vices and virtues, the mixture of allegorical (Backbiter) and diabolical (Belyal) figures, and the enactment of Death and Judgement. But it is also highly significant in the history of English theatre, largely because of a diagrammatic representation of the Castlemound as 'Theatre in the Round'.
The action begins with man's enemies, the World, the Devil, and the Flesh, declaring the nature and scope of their power. Against this background, Mankind appears flanked by his Good and Bad Angels: he is a new-born child about to begin his progress through the ages of man. He sins first by becoming a servant of the World, who sends him to Avarice and the other Deadly Sins. When Penance pierces him with a lance, he confesses to Shrift, receives absolution, and enters the Castle of Perseverance. But mankind's enemies, alerted by Backbiter, summon the Sins to a siege against the Castle. Although six of the Sins are repelled by their opposing Virtues, Avarice succeeds in enticing the ageing Mankind back to worldly goods. Only the coming of Death causes Mankind to repent. He realises that his treasure will go to an unknown heir, and he dies calling on God for mercy. The Soul reproaches the body and cries again for mercy until it is carried off to hell by the Bad Angel. The Four Daughters then debate Mankind's case, after which God rescues him.