Oculum — Philippa Dowding

As far as Miranda1 knows, there is one world: Oculum. Its dome, its walls and its garden are all there is. That's what the residents have been taught since birth. But William1 shows her something: a door in Oculum's wall. And if there is a door, there must be something on the other side…

What they don't know is that there is a shattered world outside where a ragged few, such as Mannfred, Cranker and their friends, struggle to survive among the ruins. These people have heard of a paradise within Oculum. And they, too, have found a door.