The poem follows a pilgrim who, lost in a dark wood, is guided by an esteemed ancient poet through a vividly ordered underworld. They descend through concentric circles and ditches where sinners receive punishments fitted to their vices, encountering named and unnamed damned souls, mythic guardians, and tormented landscapes. The itinerary organizes moral categories— incontinence, violence, fraud, heresy— and stages of recognition, punishment, and instruction that probe justice and human responsibility. Episodic encounters blend allegory, historical and mythical exempla, and theological reflection, framing a didactic voyage toward eventual ascent.