Emma, her younger brother Ethan, and their ex-Marine mother live in a brand-new condo building, which experiences semi-regular power outages as workers complete the units around them. The latest blackout hits just as they are preparing to leave town on a long weekend camping trip. Then the car won't start, their cellphones are dead. They canoe over to the islands, just offshore, to wait it out. But as people become increasingly desperate to find food and shelter, even the island isn't safe. Soon the threat of violence becomes all too real.