A group of survivors have been living on a large boat since the undead apocalypse began. No one has been ashore and supplies are fast running out. Teenagers Jake and Lucy lead a small group into the city to hunt for food and medicine and look for other survivors and desperately try to stay alive in a city swarming with zombies. As the zombie attacks intensify, the group is cut off from the boat. Killing zombies is one thing. But sooner or later, one of the survivors will be bitten. What then?