The journey begins in the middle of life, in a dark wood where the straight way is lost. Dante descends through nine circles of Hell, each reserved for a different category of sin, guided by Virgil, meeting the damned and hearing their stories. The punishments are precisely fitted to the crimes, a principle called contrapasso. The poetry is dense with historical reference, theological argument, and personal vendetta. Ugolino gnawing his enemy's skull; Francesca and Paolo swept forever by the wind of passion; Ulysses burning in his flame: the images are inexhaustible.