When the familiar world has been devoured by apocalypse, the islands of safety among its ruins become especially valuable. That is why any Object that accepts refugees from the wastelands on its territory must impose quarantine. No one is afraid of the procedure—everyone knows it’s just a formality—until trouble actually arrives. Due to sabotage carried out by an unknown being, quarantine at Object-21 starts a countdown. People trapped inside have only a little time left to determine where the threat comes from. They understand perfectly well: this time, not everyone will survive.