Nick and Ava have become friends over the fact that they're the only upper classmen who still ride the bus to school. And every day, they see the same boy--who they call The Kid--walking along the train tracks, even when the weather is terrible or when he's clearly fighting a bad cold.
When Nick notices the mysterious boy practically sprinting along the tracks one day and he doesn't show up the next, Nick and Ava begin to wonder if something...