Ransom is so desperate for air that he almost just lets go, observing, almost abstractedly, that he is about to die. But he suddenly finds himself surfacing on a pebbly beach, cursing and fighting with Weston’s body once more. Soon he’s astride Weston’s body, desperately gripping its throat. He counts to a thousand before he dares let go, long after the body has gone limp. He has no idea if the voice that had been speaking to him for the past few hours was really some fragment of Weston or not, but at this point, there’s nothing else he can do.
Ransom finally appears to put an end to Weston’s body once and for all, though it’s not yet clear whether the evil inside him will be rendered powerless, as Ransom has hoped.
Ransom decides to wait until the morning to examine the body by daylight, so he passes the time by reciting all the epic poetry he can remember. But eventually, he discerns that it’s no good waiting for light—somehow, he and Weston surfaced within a massive cavern. Fighting despair, he inches his way along a cliff face in the pitch blackness, and he gropes along in this way for a long time. He judges distances by shouting and eventually finds and follows a stream.
After all this, Ransom isn’t yet safe—he has to find his way out of the darkness, his physical blindness symbolizing his uncertainty of the path ahead. He has to press forward despite his fear and ignorance, trusting in Maleldil just as before.
Eventually, the stream leads Ransom toward a reddish, dim light. The light comes from an upper cavern, accessed by a narrow fissure. Hungry for the light, he gathers a pile of rocks and eventually manages to jump, climb, and claw his way through the opening into the larger chamber above. He finds himself in a vast hall filled with firelight, a shallow river running through it. When he sits down to collect himself, he is once again struck with a feeling of despair, fearing that Weston’s view of the world is right. In fact, he’s hardly surprised when the broken, corpse-like form of the Un-man soon drags itself through the hole, too, followed by a massive, many-legged, insect-like creature.
In Ransom’s solitary struggle through the cavern, he is again tempted to doubt the goodness of Maleldil’s plan and the belief that there’s any meaning in the universe. At last, it appears that the Un-man has sufficiently animated Weston’s broken body to follow and threaten Ransom once more.
Ransom is angry, realizing that the Un-man is trying to frighten him, both with the despairing thoughts and with this crawling creature. He yells rather foolishly at it to get out of his brain, then, with a desperate prayer, smashes a stone into the Un-man’s face. At this, the strange creature seems to lose its horrible appearance, and it retreats awkwardly back into the lower cave. Ransom drags the Un-man’s body to the edge of a cliff and pushes it into the sea of fire below. Too exhausted to move further that day, Ransom drinks deeply from the stream and falls asleep.
Ransom finally destroys Weston’s body once and for all, its attempt to manipulate and frighten him seeming childish and silly in the end. This almost anticlimactic passage suggests that, in the end, steady, persevering faith will outlast the worst that evil can throw at it.