Mandy is an orphan (why Disney never made a movie out of this, I'll never know) and she lives in a big sprawling orphanage in the midst of lots of land, somewhere in England (I think, at least that's always the impression I had, but that could have come from Julie Andrews' voice in my head as I read the book.)
She's an independent sort and one day she climbs over the garden wall to explore the land beyond the orphanage grounds. There she finds a rundown little cottage in need of a young girl's touch. The rest of the story takes us through Mandy's adventures as she works to fix up her secret hideaway and what happens to her on one dark and rainy night.
Mandy is a squeaky clean, lovely read for any young girl (but boys might like it too). It recently celebrated it's 35th year in print (okay, don't do the math there...) and it is well deserved.