Doctor Who (1963) Season 18 Episode 12 Full Circle (4)

The Doctor and his companions, Romana and Adric, find themselves on the planet Alzarius in E-Space, where they encounter a group of stranded space colonists who are trying to repair their ship. However, the Doctor soon realizes that there is something strange about the planet and its inhabitants.

The story follows two parallel plotlines, one involving the colonists and their struggle to repair their ship, and the other exploring the planet and its secrets. The colonists are trying to get back to their homeworld, Terradon, but they are hindered by several obstacles including malfunctioning technology and hostile creatures known as Marshmen.

Meanwhile, the Doctor, Romana, and Adric discover that the planet is in fact a closed system, meaning that it has no natural satellites or other planets in its vicinity. They also discover that the Marshmen are not simply mindless creatures, but are instead intelligent and possibly the original inhabitants of Alzarius. As they dive deeper into the mysteries of the planet, they uncover a complex web of interconnected systems and cycles that ultimately lead them to the heart of Alzarius itself.

The episode explores themes of evolution, ecology, and the cyclical nature of life and death. It raises the question of whether it is ethical for the colonists to disrupt the natural order of the planet, and whether the Marshmen deserve to be driven away from their home. The Doctor, as always, acts as a mediator, trying to find a compromise between the two sides.

Full Circle is a classic Doctor Who episode that showcases the show's unique blend of science fiction, mystery, and adventure. It features memorable characters, intriguing plot twists, and some of the most iconic villains in the history of the show. It is a must-watch for any Doctor Who fan, and a great way to introduce newcomers to the show.