Arla was born into a family without money and was mentored by seamstress Keppy Devoni. She went on to have a number of young apprentices, all of whom she taught how to make Megeshra stew, including one who was like a son to her. Despite this, she handed him over to the authorities upon learning that he was part of the resistance. (AUDIO: The Truth of Peladon)
Employed by Barok, Arla was to make a Cloak of Coronation for the King and was assisted by the Eighth Doctor, who initially claimed to be her new apprentice before implying that he worked for Barok. She was imprisoned for three days after the Doctor tricked her into including an Arcturan star map in the cloak and was visited by him each night, visiting the Loomhouse, the Great Lake of Undoing and Barok's private rooms where she learnt of his deference to the Arcturans.
Arla was convinced of the need for rebellion and, at the coronation, killed Barok with a sonic blaster supplied by Ssilas. The Doctor, who wanted him to stand trial, told the people of her crimes and how she had assisted him, leaving her to await their judgement. (AUDIO: The Truth of Peladon)