Corbo was the home world of a feathered humanoid race capable of flight. It had two stars. Its terrain consisted of huge barren cliffs that were rich in minerals. A green-skinned humanoid race attempted to invade Corbo with an army led by Lohk, but they were defeated and killed by Ulla's devil-birds, which also captured members of an Earth-Mars expedition which had arrived on the planet to collect mineral samples; only Jack and Dot Strong were left behind.
The First Doctor arrived on Corbo in a swamp, the TARDIS materialising on a pile of bones. He found Lohk's broken sword, narrowly escaped one of the devil-birds, and met Jack and Dot, who told him what had happened to the spaceship crew. He took the children to the cliffs, where they found the base where the devil-birds were kept. They stopped Ulla from executing Strong and escaped with the spaceship crew to the TARDIS. (PROSE: The Devil-Birds of Corbo)