The TARDIS lands on the planet Karn amidst the wreckages of other spacecraft. The planet is bleak, and the weather conditions are turbulent. The Doctor believes he has been sent to Karn by the Time Lords.
The sisterhood is the main occupant of the planet Karn, in the same constellation as Gallifrey. There is also a scientist, Doctor Solon, and his assistamt, working on a horrendous experiment. Solon aims to take the brain of an executed Time Lord criminal, Morbius, and transplant it into another body, returning to him the gift of life.
The Sisterhood believe the Doctor has been sent by the Time Lords to steal their Elixir of Life. They kidnap him and attempt to burn him at the stake until he is rescued by Sarah.
The Doctor asks the Sisterhood for help, and in return restores their dying Elixir flame. The Doctor and Sarah return to Solon's citadel where he releases cyanide gas, killing Solon. The experiment is already complete, and the Doctor challenges Morbius to a mind-bending contest, which mentally drains both Time Lords. The Sisterhood use their mental capabilities and force Morbius over the edge of a cliff.
