In his first adventure, Elwin Ransom was kidnapped by Weston & Devine to Malacandra. The second adventure starts off very differently.
Ransom is sent by an eldil to Perelandra, which we call Venus. He is not given any clear instructions or mission, only told that his presence is needed there. On his arrival, Ransom finds himself in the middle of an ocean. Just when he starts to panic about going under and drowning, he sees floating, mobile islands made up of some kind of vegetable matter. These islands are constantly shifting, and, being flexible, conform to the shape of the waters beneath them. They have flora and fauna of their own, which Ransom finds eminently agreeable.
After exploring for a while, Ransom meets an intelligent inhabitant of Perelandra, a green-skinned, but otherwise entirely human-appearing woman. After talking with her for a while in the language he learned on Malacandra, Ransom comes to understand that she and the King whom she often refers to are the first of their kind. They are, effectively, this world's Adam and Eve. Ransom also discovers that they have been given one command: They are not to sleep overnight on the fixed land, but to live on the floating islands.
SPOILERS UNTIL MARKED OTHERWISE
Not long after meeting the Lady, Ransom finds them joined by another Earthman, Dr. Weston. Weston, it turns out, has broadened his horizons and is now no longer strictly interested in physics and physical phenomenon. In fact, he is very concerned about the spiritual fate of mankind. After a long, rambling discourse about the nature of spirituality and man's place in the universe, Weston invites the spirit which drives man forward (which he identifies with the Devil) into his own body. He suffers some kind of seizure, and Ransom fears he is gravely ill, perhaps even dying.
After sleeping that night on the island (it was never forbidden to him), Ransom wakes up to find Weston gone, and himself alone. He rides a great fish (I imagine them as something like dolphins) to find the Lady on one of the floating islands. When he arrives, he finds her in discourse with Weston, but not the man he knew. Ransom finds Weston grotesquely altered, looking like a dead man puppeted with strings. He dubs this creature the Unman.
He finds the Unman earnestly trying to convince the Lady of the necessity of her staying on the fixed land, in contravention of Maleldil's command. Thus commences a debate lasting many days in which Ransom argues against the Unman's corrupting influence. Although Ransom does his best, he can tell he is losing ground, and the Lady is in grave danger of falling, corrupting this entire world as Earth was before.
Finally, he comes to the realization that he must put a stop to this, and the most effective way of doing so is by physical combat. After a great internal struggle, Ransom resigns himself to this, believing that it will almost certainly mean his death. When he confronts the Unman and strikes him, and the fight begins in earnest, he finds that contrary to his fears, physically the fight is just one middle-aged academic against another. The two fight for a long time, and Ransom chases the Unman, both riding the great fishes, away from the island. Finally, the Unman manages to drag Ransom down under with him. Although he fears drowning, Ransom finally surfaces on solid land, still grappling with the Unman. He kills him and awaits the coming of day.
After many hours, Ransom realizes that day is never coming because he's underground. He begins a long journey to the surface. When he reaches daylight at last, he spends several days recuperating from his fight in a sweet valley. Then he finds himself guided by the local animals to a nearby peak, where he meets the oyarsas of Perelandra and Malacandra. The three of them await the arrival of the Lady and the King. These thank Ransom for his work in protecting them from temptation. The King then explains his role in the future of the Solar system and how the siege of the Silent Planet (Earth) will be broken and her people set free from the evil eldil who rules her.
There follows an ecstatic hymn to Maleldil, praising him and all his creation. At the end, Ransom is told a full Venusian year (225 Earth days) has passed, and it is time for him to return home, which he does.
END SPOILERS
Honestly, this is my favorite of the three books. The world C.S. Lewis imagines here is perhaps one of my favorite alien worlds in s.f. It is sufficiently alien that it could never for a moment be mistaken for Earth, but also described in clear, comprehensible terms that we can visualize.
The temptation of the Lady is also fascinating to watch. Lewis shows how evil will appeal to us from every possible angle, through our intellect, through our self-image, through rational argument, through corrupt story-telling (hello, Hollywood). Also, much of that is clearly taking a crack at what, in our day, has grown into feminism.
The song of praise for God and the beauty of his creation and the beauty of hierarchy within that creation is transcendant.
It's been a while since I last read That Hideous Strength, so I may be wrong in this, but I believe this is also the most explicitly Christian book of the three. There are clear references to Maleldil (God) becoming man, joining us on Earth for a time, and dying as a sacrifice.
Is this my favorite Lewis fiction? I don't know. There's some stiff competition. The Great Divorce is another possibility. I need to re-read Til We Have Faces someday and think about that one some more. Perelandra is definitely near the top of the list, though. If you haven't read it yet, I highly recommend it.
