Rua

 was a human colony planet. Its name was derived from the Hebrew word for "wind" or "spirit", on account of the high winds on the planet. The first colonists experienced winds of over 300 kilometres per hour.

Susan Foreman arrived on Rua while searching for antibiotics for the First Doctor, however she discovered that antibiotics had since fallen out of use, due to immunity caused by past overuse. Instead, the planet had developed Nanomedicines which served many functions in the way of healing.

The planet was under lockdown, when Susan arrived, having been threatened by biohacker and terrorist known as "the Butcher". Susan encountered Kendrick and his team who were attempting to stop the Butcher. She helped them to reach him, under duress, and embarked on her own diplomatic mission to negotiate with the Butcher, before he was shot by Kendrick. Distressed at this outcome, Susan returned to the TARDIS with medication for the Doctor. (AUDIO: The Sleeping Blood)