Four Hundred Dawns

The TARDIS materializes on a planet characterized by an eerie, profound silence, prompting the Doctor to ponder the paradox of a life-conducive world devoid of sound. A mysterious, squat, dome-shaped machine, which Vicki nicknames a 'Chumbley,' soon appears, meticulously investigating the TARDIS's exterior by touch, suggesting a blind but intelligent presence. Venturing outside, the Doctor, Vicki, and Steven encounter another Chumbley, which demonstrates a powerful, rod-like weapon by incinerating nearby vegetation, coercing them into moving in a specific direction. As they proceed, two emotionless Drahvin warriors, with rigid features and large guns, ambush the Chumbley, immobilizing it with a metal mesh. They claim to rescue the travelers and escort them to their leader, Maaga, aboard a dilapidated spaceship. Inside, Maaga immediately reveals a deadly, existential war with the Rills, the Chumbley controllers, over the planet. She explains their own crash-landing while seeking a new colony world and the planet's imminent destruction in fourteen dawns, information she attributes to the Rills. This revelation establishes the core conflict and the immediate, life-threatening stakes for the TARDIS crew, forcing them into an unexpected alliance.

Maaga details the Drahvin society, describing a militaristic, female-dominated structure where men exist solely for procreation and soldiers are 'cultivated in test tubes' as 'inferior products' designed to fight and kill. She recounts their crash-landing, attributing it to a Rill attack, and expresses profound distrust of the Rills' claims about the planet's impending destruction, believing it a trap. When a Chumbley approaches the Drahvin ship to transmit a message, Maaga orders its destruction with flame, refusing to hear what she deems Rill lies, though the Chumbley survives and retreats. The Doctor, highly skeptical of Maaga's narrative and the planet's supposed doom, insists on verifying the celestial mechanics himself. Maaga, unwilling to allow all three to leave, demands a hostage to ensure their return; Vicki bravely volunteers to stay behind. As the Doctor and Steven return to the TARDIS, they discover Chumblies attempting to breach its force field with a drill and light beam, but the TARDIS's defenses hold. Meanwhile, Vicki, left alone in the Drahvin living quarters, overhears Maaga vehemently berating her soldiers for their incompetence and expressing extreme, fear-driven revulsion towards the Rills, describing them as 'creeping, revolting, green monsters' with 'slimy claws.' This overheard tirade exposes Maaga's true, desperate nature and casts significant doubt on her earlier claims.

The Chumblies, after failing to penetrate the TARDIS's robust force barrier with their drill and light beam, transmit a brief message and retreat. The Doctor and Steven emerge from their hiding place, confirming the TARDIS remains untouched, its defenses proving impenetrable. With the immediate threat gone, the Doctor, now more determined than ever, prepares to re-enter the TARDIS, his scientific objective to verify the planet's stability solidified. Steven, his distrust of Maaga growing, stands ready to assist. Unbeknownst to them, Vicki, left as a hostage aboard the Drahvin spaceship, has just uncovered Maaga's profound fear and hatred of the Rills through an overheard tirade, revealing a deep-seated prejudice that contradicts Maaga's earlier, more composed narrative. This critical piece of information fundamentally alters the audience's understanding of the conflict. The episode concludes with the Doctor and Steven poised to re-enter the TARDIS, their mission to uncover the truth about the planet and the warring factions now clearer and more urgent, while Vicki remains in a precarious position, privy to Maaga's true, manipulative nature.