The narrative follows a pilgrim who, guided by an authoritative classical figure, descends through a vividly structured underworld divided into concentric circles that punish different kinds of moral failings. Along the way the pilgrim encounters tormented souls whose individualized sufferings illuminate ethical principles and personal and civic grievances, and learns an ordered cosmology where divine justice metes out fitting retribution. The journey mixes vivid allegory, moral analysis, and political and autobiographical allusion, preparing the traveler to ascend toward purification in the subsequent parts of the poem.