Ransom, a philologist and professor on sabbatical is kidnapped by two mad scientists and taken to the distant planet of Malacandra. There, he escapes from his captors and is taken in by a clan of hrossa, an otter-like species. Slowly, he learns their language and is eventually invited to join them on a hunt for a sea-monster known as a hnakra. Just before they set sail, an ethereal being called an eldil tells them that Ransom must go to see Oyarsa, the spirit who rules the planet. They continue with the hunt, and one of the hrossa is killed by the scientists.
Ransom sets out to go see Oyarsa as commanded, and his helped on his journey by the a sorn, another native species on Malacandra. When he arrives he meets the third species, the pfifltriggi. Oyarsa asks him about his world, known by them as "Thulcandra", the silent planet. The scientists arrive and try unsuccessfully to intimidate the Malacandrans. Finally, Oyarsa sends them back to Earth, and Ransom decides to go home as well.
