Sebastian Musgrove is stationed on Monitoring Base XL-7, alone except for two robots. He has a hologram of his former girlfriend, Tarla McCail, who was killed by the Daleks. The base has been experiencing power fluctuations, there are storms outside, and Sebastian thinks there is something on the planet with him.
They arrive on the base and find Sebastian. He seems nervous in their presence, and the Doctor offers to check out the power outages. Sebastian starts seeing things, like his hologram coming to life. Nyssa sees the hologram as well.
The Doctor's investigations reveal that there is something on the planet that is draining the base's power. When the base comes under attack, Sebastian tries to offer the Doctor and Nyssa as sacrifices to whatever is on the planet, but the Doctor remembers something about this place and leaves the room.
Nyssa finds him with a creature of light. It extends a tendril towards him, and Nyssa pushes him away, trying to save him. He yells at her, saying it was trying to communicate with him. The tendril then enters Nyssa, and she begins to speak.
The creature is Telxzana, the last of the Pzorswihr. She is part of the planet, and she has been trying to communicate with Sebastian, but being electro-sensitive, her attempts shorted out the base's power. She has been trying to tell him that she is dying, and he must leave the planet.
When the Doctor and Nyssa leave, they promise Sebastian they will send a survey ship to the base to pick him up.
In the TARDIS, the Doctor tells Nyssa that he remembered hearing about the instabilities on the planet when he won it, and he had always meant to check it out.
- Nyssa has a breakfast of toast, marmalade and coffee.
- The Doctor uses the alias Dr John Smith.
- The Doctor mentions Kublai Khan.
- The Doctor won the planet in a game of poker against a Draconian.
- The stories in Decalog 2 have a common theme of homes owned or acquired by the Doctor. The home in this story is the planet on which the base is located.
- Nyssa recalls their recent battle against the Cybermen, where they lost Adric, (TV: Earthshock) and Tegan returning to Heathrow Airport. (TV: Time-Flight)