Shhh, listen . . . hear that? Is it the breeze in the tall grass? Or is it . . . something—somebody—sinister? The kids of Cowslip Grove are putting on a school play, and Kat, Levi, Donte, and their friends all have parts.

But at rehearsal one day, a piece of chalk leaps up on its own and starts writing on the blackboard. Soon the kids learn they are being stalked by the mysterious "Little Nobody"—an invisible child with no memories.

As the kids begin to unravel the mystery behind Little Nobody, they accidentally reveal a strange and secret world—along with the true fates of many long-lost children and creatures. But something else is watching: an undead enemy that hopes to manipulate Little Nobody into bringing great harm to Cowslip Grove. And it will take everything the children have to defeat it.