Inferno opens on the evening of Good Friday in the year 1300. Traveling through a dark wood, Dante Alighieri has lost his path and now wanders fearfully through the forest. The sun shines down on a mountain above him, and he attempts to climb up to it but finds his way blocked by three beasts—a leopard, a lion, and a she-wolf. Frightened and helpless, Dante returns to the dark wood. Here he encounters the ghost of Virgil, the great Roman poet, who has come to guide Dante back to his path, to the top of the mountain. Virgil says that their path will take them through Hell and that they will eventually reach Heaven, where Dante’s beloved Beatrice awaits. He adds that it was Beatrice, along with two other holy women, who, seeing Dante lost in the wood, sent Virgil to guide him.

Virgil leads Dante through the gates of Hell, marked by the haunting inscription “abandon all hope, you who enter here” (III.7). They enter the outlying region of Hell, the Ante-Inferno, where the souls who in life could not commit to either good or evil now must run in a futile chase after a blank banner, day after day, while hornets bite them and worms lap their blood. Dante witnesses their suffering with repugnance and pity. The ferryman Charon then takes him and his guide across the river Acheron, the real border of Hell. The First Circle of Hell, Limbo, houses pagans, including Virgil and many of the other great writers and poets of antiquity, who died without knowing of Christ. After meeting Horace, Ovid, and Lucan,

Dante continues into the Second Circle of Hell, reserved for the sin of Lust. At the border of the Second Circle, the monster Minos lurks, assigning condemned souls to their punishments. He curls his tail around himself a certain number of times, indicating the number of the circle to which the soul must go. Inside the Second Circle, Dante watches as the souls of the Lustful swirl about in a terrible storm; Dante meets Francesca, who tells him the story of her doomed love affair with Paolo da Rimini, her husband’s brother; the relationship has landed both in Hell.

In the Third Circle of Hell, the Gluttonous must lie in mud and endure a rain of filth and excrement. In the Fourth Circle, the Avaricious and the Prodigal are made to charge at one another with giant boulders. The Fifth Circle of Hell contains the river Styx, a swampy, fetid cesspool in which the Wrathful spend eternity struggling with one another; the Sullen lie bound beneath the Styx’s waters, choking on the mud. Dante glimpses Filippo Argenti, a former political enemy of his, and watches in delight as other souls tear the man to pieces.

Virgil and Dante next proceed to the walls of the city of Dis, a city contained within the larger region of Hell. The demons who guard the gates refuse to open them for Virgil, and an angelic messenger arrives from Heaven to force the gates open before Dante. The Sixth Circle of Hell houses the Heretics, and there Dante encounters a rival political leader named Farinata. A deep valley leads into the First Ring of the Seventh Circle of Hell, where those who were violent toward others spend eternity in a river of boiling blood.

Virgil and Dante meet a group of Centaurs, creatures who are half man, half horse. One of them, Nessus, takes them into the Second Ring of the Seventh Circle of Hell, where they encounter those who were violent toward themselves (the Suicides). These souls must endure eternity in the form of trees. Dante there speaks with Pier della Vigna. Going deeper into the Seventh Circle of Hell, the travelers find those who were violent toward God (the Blasphemers); Dante meets his old patron, Brunetto Latini, walking among the souls of those who were violent toward Nature (the Sodomites) on a desert of burning sand. They also encounter the Usurers, those who were violent toward Art.

The monster Geryon transports Virgil and Dante across a great abyss to the Eighth Circle of Hell, known as Malebolge, or “evil pockets” (or “pouches”); the term refers to the circle’s division into various pockets separated by great folds of earth. In the First Pouch, the Panderers and the Seducers receive lashings from whips; in the second, the Flatterers must lie in a river of human feces. The Simoniacs in the Third Pouch hang upside down in baptismal fonts while their feet burn with fire. In the Fourth Pouch are the Astrologists or Diviners, forced to walk with their heads on backward, a sight that moves Dante to great pity.

In the Fifth Pouch, the Barrators (those who accepted bribes) steep in pitch while demons tear them apart. The Hypocrites in the Sixth Pouch must forever walk in circles, wearing heavy robes made of lead. Caiphas, the priest who confirmed Jesus’ death sentence, lies crucified on the ground; the other sinners tread on him as they walk. In the horrifying Seventh Pouch, the Thieves sit trapped in a pit of vipers, becoming vipers themselves when bitten; to regain their form, they must bite another thief in turn.

In the Eighth Pouch of the Eighth Circle of Hell, Dante speaks to Ulysses, the great hero of Homer’s epics, now doomed to an eternity among those guilty of Spiritual Theft (the False Counselors) for his role in executing the ruse of the Trojan Horse. In the Ninth Pouch, the souls of Sowers of Scandal and Schism walk in a circle, constantly afflicted by wounds that open and close repeatedly. In the Tenth Pouch, the Falsifiers suffer from horrible plagues and diseases.

Virgil and Dante proceed to the Ninth Circle of Hell through the Giants’ Well, which leads to a massive drop to Cocytus, a great frozen lake. The giant Antaeus picks Virgil and Dante up and sets them down at the bottom of the well, in the lowest region of Hell. In Caina, the First Ring of the Ninth Circle of Hell, those who betrayed their kin stand frozen up to their necks in the lake’s ice.

In Antenora, the Second Ring, those who betrayed their country and party stand frozen up to their heads; here Dante meets Count Ugolino, who spends eternity gnawing on the head of the man who imprisoned him in life. In Ptolomea, the Third Ring, those who betrayed their guests spend eternity lying on their backs in the frozen lake, their tears making blocks of ice over their eyes. Dante next follows Virgil into Judecca, the Fourth Ring of the Ninth Circle of Hell and the lowest depth. Here, those who betrayed their benefactors spend eternity in complete icy submersion.

A huge, mist-shrouded form lurks ahead, and Dante approaches it. It is the three-headed giant Lucifer, plunged waist-deep into the ice. His body pierces the center of the Earth, where he fell when God hurled him down from Heaven. Each of Lucifer’s mouths chews one of history’s three greatest sinners: Judas, the betrayer of Christ, and Cassius and Brutus, the betrayers of Julius Caesar. Virgil leads Dante on a climb down Lucifer’s massive form, holding on to his frozen tufts of hair. Eventually, the poets reach the Lethe, the river of forgetfulness, and travel from there out of Hell and back onto Earth. They emerge from Hell on Easter morning, just before sunrise.