Board Thread:General Discussion/@comment-26467148-20180202234507/@comment-32173189-20180203060405

I get the feeling they're going the Ronnie Anne route, in which she doesn't physically appear in the episode she's mentioned in (Heavy Meddle), but appears in a later episode (Save the Date). In this case the new girl is probably Stella and her first actual appearance will be in "Be Stella My Heart", since it wouldn't make much sense to hype up a character and just her for a lesson of the day.