The Inferno: Novel Summary: Canto 9

Seeing Dantes fear, Virgil tries to appear confident, and he listens attentively for some indication that the promised help is near. He still seems worried-the help seems so long in coming! And if it doesnt . . . . Dante imagines the worst, and asks whether anyone from the First Circle, where Virgil dwells, has ever come down this far. Virgil answers that he himself was once conjured by a witch to go down to the very depth of Hell and bring back a shade, so he does indeed know the way, and Dante shouldnt worry.
But now Dante sees on the tower before them the three Furies, in the shape of women with snakes for hair, raging and threatening to bring out the gorgon Medusa, whose gaze would turn Dante to stone. Virgil orders Dante to turn around and covers Dantes eyes with his hands, since if Dante were once to see Medusa, he would never return to the light of day.
Then over the waves comes a fearful sound, as of a mighty wind striking a forest, and Virgil drops his hands and urges Dante to look. Indignant, yet calm and untouched, an angel is crossing the marsh, and he opens the gate easily and reproaches the fallen angels with vainly resisting Gods will. Then he goes on his way, and Dante and Virgil enter secure.
Once inside the gates, Dante sees a great plain covered with tombs, and the tombs are made red hot by the flames that surround them. The lids of the tombs are open, and Dante hears the groans of those within. Virgil explains that they are all heretics.
Medusa the gorgon is a symbol of despair, and despair can easily seize on those who first realize they have chosen their own misery. A realization of a deeper force that wills growth and joy is needed here.