Polly and Gertie can't wait to go to the festival to compete against other schools. This time, they're going to the Opera House. And that means they'll be famous.When Miss Badger bans Polly from the choir for singing out of tune, Gertie refuses to go to the festival without her best friend. The headmistress, Mrs Godbolt, can't have that because Gertie has the best singing voice in the whole school.Polly comes up with a brilliant idea. She says she's a great actress and could easily mime instead of singing. But Miss Badger is horrified. She tells the headmistress that Polly stunk out the classroom. Surely they can't risk letting her go to The Opera House? After all, how could they trust her not to sing? And what if she made disgusting smells when their school was performing?Well, no way is Polly letting anyone stop her from going to The Opera House. How else can she become famous? And she's not leaving Mange behind either. 'Cause Great Aunt Mabel is back and she hates dogs. The old crab-apple would only stick him in the shed with the chook poo and feed him fish heads for dinner.