Her parents have to fix the place up before they can sell it, and Sarah and her brother, Billy, have to help. But the tedious work turns into a thrilling mystery when Sarah discovers an unfinished letter her grandmother wrote: Strange things are happening behind the bookcase. . . . Sarah's mother dismisses the letter as one of Grandma Winnie's crazy stories, but Sarah does some investigating and makes a remarkable discovery: behind the bookcase is a doorway into Scotopia, the land where shadows come from. With a talking cat named Balthazat as her guide, Sarah begins an unforgettable adventure into a world filled with countless dangers. Who can she trust? And can she face her fears, not only in Scotopia, but also back at Grandma Winnie's house, where more secrets and strange goings-on await her?