The Golden Ghost — Marion Dane Bauer

Delsie knew it wasn't a good idea to dare her best friend Todd to explore the abandoned houses by the old mill. But she couldn't back down after the words slipped out of her mouth. Together the two friends bike to the mill and try the door of each abandoned house. They are all locked . . . except one. Delsie and Todd sneak inside and discover two strange things. Someone is living there. And something doesn't want Delsie to leave. It's a dog, a strange golden dog, that only Delsie can see!