Theatre director Caden Cotard (Philip Seymour Hoffman) is mounting a new play. He gathers an ensemble cast into a warehouse in Manhattan's theatre district. He directs them in a celebration of the mundane, instructing each to live out their constructed lives in a small mock-up of the city outside. As the city inside the warehouse grows, Caden's own life veers wildly off the tracks. The shadow of his ex-wife Adele (Catherine Keener), sneers at him from every corner. He's helplessly driving his marriage to actress Claire (Michelle Williams) into the ground. As the years rapidly pass, Caden buries himself deeper into his masterpiece. Populating the cast and crew with doppelgangers, he steadily blurs the line btw the world of the play and that of his own deteriorating reality. As he pushes the limits of his relationships, both personally and professionally, a change in creative direction arrives in Millicent Weems, a celebrated theatre actress who may offer Caden the break he needs.