The Host comes to Morgul-vale. Frodo and Samwise escape and begin their journey along the road to Barad-dur.
"Vale of the Morgul", by Alan Lee
These are some of the most desperate days of our story. The remnants of the force of the West begin to understand the horror of the role they have committed themselves to play as they enter the area surrounding Minas Morgul: ". . . the air of the valley was heavy with fear and enmity", even though the orcs and the Nazgul are abroad.
But it is Frodo and Sam who are the most desperate. While the beginning of the chapter entitled "Mount Doom" tells us that they had entered a "wilderness of fear", they were "too worn out even to feel much fear." While their abduction by orcs had, ironically, forced them farther along their road than their own wills would have taken them, it has left Frodo utterly spent, and Sam becomes the leader of the quest. It is only then that he begins his dance with despair: "But even as hope died in Sam, or seemed to die, it was turned to a new strength. Sam's plain hobbit-face grew stern, almost grim, as the will hardened in him, and he felt through all his limbs a thrill, as if he was turning into some creature of stone and steel that neither despair nor weariness nor endless barren miles could subdue."
I have to admit to skipping this part of the story on many readings. But it is really some of Tolkien's best writing, as the hobbits slowly divest themselves of all but their own wills--and their Burden.