moomins-at-sea:

"Poor Ninny. She's looked after by an aunt who doesn't like her and is really horrible to her, and only does it because she thinks it's her duty. It wouldn't be so bad if she just got mad and yelled at 
her, but she's cold and sarcastic which is much worse. --- Anyway,
she just went on being more and more horrible to her, so that in the
end, Ninny was so upset she became invisible."
Or, how Ninny became visible again.