Crandor was a strange world in Sector 12. It may have been an artificial planet. It was either at the centre of an unusual black hole, or simply appeared to be as a result of the Thaarn's gravity generator.
Crandor appeared to exist in a state of permanent darkness, although there was a breathable atmosphere and normal gravity. Parts of its surface were littered with scrap and rubble, the remains of ships and asteroids cannibalised for herculanium and other vital elements.
The Thaarn had absolute power on Crandor, ruling through his emissary the Caliph of Crandor. The population was effectively enslaved and made to work on expanding the Thaarn's power, though slaves running away was not unheard of. Energy isolators meant that only the Thaarn's technology worked on Crandor, and computers - even simple calculators - were forbidden.
The Liberator was drawn in to Crandor where its herculanium hull made it a great prize. The crew were captured by the Caliph. Avon and Tarrant were put to work with the Caliph's senior technician, Groff, and Cally was taken to the Thaarn who seemed strangely obsessed with her. Attempts by the Caliph to locate Orac failed, while the scrappers attempting to dismantle the Liberator fell victim to its defence system.
Cally persuaded the Thaarn to deactivate the energy isolators, meaning the Liberator crew could use their handguns to escape. With the gravity generator reversed the ship was able to escape, although Crandor itself was destroyed by the gravity shift. A second, smaller craft also escaped, which the crew assumed to be the Thaarn abandoning his world.