Derek Cho (Steven Yeun) is having a really bad day. After being unjustly fired from his job, he discovers that the law firm's building is under quarantine for a mysterious and dangerous virus. Chaos erupts throughout the office as the victims of the disease begin acting out their wildest impulses. Joining forces with a former client (Samara Weaving) who has a grudge of her own, Derek savagely fights tooth and nail to get to the executives on the top floor and settle the score once and for all.