Doctor Who

Season 18, Episode 20

Episode Title: Warriors' Gate (4)

Air Date: 1981-01-24

Overview:

The Doctor deduces that the freighter is a slave ship loaded up with Tharils to be sold as time machine components, but the immense weight of Rorvik's damaged ship, designed to contain the Tharils, is now collapsing the fragile void of the micro-universe in which they're all stuck, pulling everything inside ever closer.