Oscar and Stella are married, and their cohabitation has taken on all the mundane trappings of routine. But when their neighbor Poortman goes on vacation and leaves them his key so that they can water his plants, the empty apartment across the terrace becomes a place where Oscar and Stella's imaginations can run wild. Stella soon stumbles upon a stranger sleeping in Poortman's bed, at which point events take a significant turn, and the line between fantasy and reality becomes increasingly blurred.