The Doctor and Vicki encounter the Rills and learn the situation is more complex than they thought while Steven finds the Drahvins' hospitality ever more perilous.
Did You Know?
This episode was watched by 11.3 million viewers on its original transmission. See more
In "Air Lock", the machine that converts air to ammonia has a piece fall off when the Doctor bumps it, midway through his speech. See more
There's a Chumbley coming! Quickly!