The Fourth Doctor takes Leela to the colony planet Delafoss. However it turns out to be a battle site for one of the Earth Alliance's wars with the Eminence. The Eminence are constructing a warship, the Infinite, to wipe out humanity.
This is the first encounter the Doctor has with the Eminence, who had already appeared in "The Seeds of War", featuring the Sixth Doctor, and would go on to play a big part in the Time War, against the Eighth Doctor.
Tropes:
- Continuity Nod: Leela mentions her father Sole.
- Human Shield: The Eminence have thousands of humans on the Infinite acting as this.
- "I Know You're in There Somewhere" Fight: The Doctor tries this on Davent, who pauses when his family is mentioned.
- The Needs of the Many: How Zarith justifies trying to destroy the Infinite, despite the thousands of prisoners on board. The Infinite could destroy billions, so all those humans are expendable.
- Our Zombies Are Different: Those infected by the Breath of Forever are turned into Infinite Warriors, with orange eyes and cracked grey skin, under the control of the Eminence.
- Pretend to Be Brainwashed: The Eminence use the Breath of Forever on the Doctor, hoping for him to be the commander of the Infinite. However his respiratory bypass system enables him to withstand this and bring about the Infinite's defeat.
- Shoot the Dog: Despite the Doctor's efforts, Sarla is shot dead because the Eminence have no use for her.
- War Is Hell: Comes across a lot in the story.
