Welcome to the Hollow Universe: a growing collection of stories that all orbit one idea, that the world has more empty spaces than anyone admits, and something is always waiting to fill them. A locked door in a mystery. A gap in the woods where a fantasy creature slips through. An empty seat at school that used to belong to someone nobody remembers. Each book stands on its own, different characters, different towns, different genres, but every one of them asks the same question: what's hiding in the hollow spaces we walk past every day?