The Golden Door
Maleans were not supposed to have empathy for other beings or affection for each other. Maleans who did so were considered mutants to be destroyed. Alëza and Orsa were hunted by another Malean, Mykloz, whose mission it was to kill them.
The Sixth Doctor helped Alëza and Orsa get to the planet Bukol, where they could enter the Sanctuary and be safe from their people. After some misadventures, during which Alëza and Orsa posed as Dodo Chaplet and Steven Taylor, they safely entered the Sanctuary. (The Golden Door)