Parts: 4
Writer: Chris Boucher
Airdates: 1 January 1977 - 22 January 1977
Production Code: 4Q

Doctor: fourth
Companion: Leela

Megalomaniac of the Week: Xoanon
Creature Feature: Horda

Story: In the only village on a lush jungle planet, a young woman named Leela is cast out of her tribe for speaking against their god, Xoanon. She is pursued by assassins sent by Neeva, the high priest, but manages to escape them with the help of a fellow villager. Leela's only option is to cross the Boundary separating her village from the Beyond, where phantoms are said to roam.

In the Beyond, as Leela tries to elude the phantoms, she literally falls at the feet of a man she knows by reputation. His name is the Evil One, and he eats babies, just like the legend says. He even offers one to Leela, but she declines. But the Evil One claims not to be the Evil One. He says his name is the Doctor, and he shows Leela the device that is creating the Boundary and holding the phantoms at bay.

When the Doctor takes Leela back across the boundary, he is captured by the villagers. Neeva wishes to sacrifice him in front of the men; the Sevateem are preparing to attack their enemies, the Tesh, and free Xoanon, and the destruction of Xoanon's captor would be very inspirational. Leela helps to free him, and then the mystery begins to thicken. Xoanon speaks to Neeva with the Doctor's voice. A nearby mountain bears a carving of the Evil One - but it is the Doctor's face. The Doctor begins to suspect that he has visited this planet before, and that his influence was not benign... For the god of the Sevateem has gone mad, and unless the Doctor can rectify a mistake he made ages ago, Xoanon might just destroy the planet.