The Leisure Hive on the planet Argolis is an entertainment centre for galactic travellers. At the heart of the Hive is the Tachyon Recreation Generator, a machine with a most extraordinary performance capability and vital to the continued existence of the Argolin after their devastating war with the reptilian Foamasi …

While visiting the Hive, the Fourth Doctor and Romana are sucked into a whirlpool of treachery and deceit, and are eventually arrested on suspicion of murder …