The Underwater Menace
Ara was a servant girl in Atlantis. She hated Professor Zaroff and helped the Second Doctor oppose his plans.
Ara helped The Doctor and his companions several times. She brought The Doctor’s message to Zaroff, who stopped the priest’s sacrifice of the Doctor and his friends. She rescued Polly from the operation that would have turned her into a fish person.
She later took part in The Doctor’s plot to kidnap Zaroff, hiding Polly when guards came searching for The Doctor and his friends. (The Underwater Menace)