In the conclusion of the six-part story "The Mutants," the despotic Marshal (Paul Whitsun-Jones) of the orbiting Earth Skybase prepares to launch an invasion of the planet Solos. But thanks to the combined efforts of the Doctor (Jon Pertwee) and resistance leader Ky (Garrick Hagan), the Marshal is too late to stop the evolutionary process that will enable the Solonions to declare their independence. And what an evolution it is: Even Darwin couldn't have done better. Written by Bob Baker and David Martin, "The Mutants, Episode 6" first aired on May 13, 1972. ~ Hal Erickson, Rovi