Four children are left behind in their underground home while their parents and the others leave to see if the surface is safe again after The Disaster. However, they've been gone too long, and food is running out. But before Miriam, Isaiah, Chen and Davis can finish their plans, their home is flooded and destroyed. They barely escape it and lose everything. WIth no food, shelter or extra clothes, they realise they aren't safe yet. Adapting to live underground makes the surface dangerous for them, and they have to find cover fast. Even so, not everyone wants to help. Can they work out how to work together before it's too late?