Lars is a lonely man, who lives next door to his brother and sister-in-law, Gus and Karin in a US Midwestern Town. Whether Lars is with his family, at work or in the local Holy Grace Lutheran Church, he finds it difficult to relate to people. It emerges that Lars' and Gus' mother died when they were young, and their father turned inward on himself.
When Lars develops a delusional attachment to life-size sex doll he calls Bianca, his family blame themselves for not spotting signs of his mental illness earlier. Lars' doctor suggests this is how he is communicating his needs and working through his issues.
Despite his family fears that Lars' delusion will further isolate him from the outside world, in general, it has the opposite effect. The local community embraces Bianca and she is invited to make her own contribution, welcome to church and on the school committee and even a more suitable makeover.