The film is set in a Midwestern small town during a typically snowy winter. Lars Lindstrom (Gosling), an awkward young man, lives in the garage beside his deceased father's house. The main house is occupied by his recently returned brother, Gus (Paul Schneider), and pregnant sister-in-law, Karin (Emily Mortimer), who is delightfully overprotective of her oddball kid brother-in-law.
After years of what is almost solitude, Lars introduce Bianca, a friend he met on the internet, to them. But they are stunned and don't know what to say because Bianca is a life-size doll, not a real person and he is treating her as though she is alive. They consult the family doctor (Patricia Clarkson).