"An Apple paperback"

At Animal Ark, Mandy Hope helps her parents treat animals of all shapes and sizes. Even outside the clinic, Mandy can't resist aiding any animal in need- and sometimes even ghostly animals need her help.
Mandy and James are excited about their school trip to an old mine. While underground, Mandy begins to imagine how difficult life must have been for the ponies that used to work down there. Suddenly, she spots eyes gleaming in the darkness, watching her. But James can't see a thing! The very next night, Mandy dreams about a troubled pony.
What can it all mean- is there a horse that needs her help?