Hydra (planet)
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Hydra was a water-world invaded by the Voord led by Tarlak. The planet was almost entirely covered by water, save for one land mass. The First Doctor, Ian Chesterton, Barbara Wright and Susan Foreman helped the native Hydrans defeat the Voord invaders.
The Hydrans were unfamiliar with Earth. (AUDIO: Domain of the Voord)
