Planet (The Klepton Parasites)

An Earth-like planet was inhabited by Thains. A group of Kleptons came to this world and built an underwater city. In the 30th century they attacked a Thain city with their flying machines and destructive creeper plants, capturing many for slaves. The First Doctor, John and Gillian arrived and helped the Thains repel the invaders. They followed the Kleptons to their underwater base, freed their slaves and blew up the base. (COMIC: The Klepton Parasites)