The island seems to be the perfect home for the many children that live there. It has forests and marshes, hills and valleys, caves and beaches, cliffs and meadows. They don't know any other home, anyway. No one remembers their "Befores": the things that happened before they woke up washed ashore on the island with a crate of supplies, and one special item in a pouch around their neck. The children build shelters, take care of themselves and the others, and live a happy life, day to day. Only a few things change: new kids wash up on the shores each year, and the Leavings: in the year leading up to a child turning 16, they build a raft. On the eve of their 16th birthday, they hang up their items in the branches of the After Tree, and sail away into the horizon, never to be seen on the island again. So many questions remain: Who are these children, and why are they here?