Officially, Tristendon is a school dedicated to teaching the science of gatecraft and inter-world travel. Unofficially, it is a superhighway to the wealth of worlds—traveled by shape-shifting godlings, gate mages, and those who hunt them.

As a gate student from the impoverished Outer Reaches, Kora Featherstone stumbles into spectacular cultural faux pas as she embarks on her journey to learn gate-travel, to break caste, to find her lost friend.

Thaden follows behind, mediating each crisis, trying to find the heart he lost when he was too young to protect himself, knowing that together they could master the gates. But what begins as a simulated exercise will propel them far beyond Tristendon, and cut each of them to the bone.