Wilson Joel (PHILIP SEYMOUR HOFFMAN) is a software engineer whose wife, Liza, has just committed suicide. Understandably shocked and grieving, Wilson is just trying to get by and even news from his co-worker, Maura Haas (SARAH KOSKOFF), that a businessman, Tom Bailey (STEVEN TOBOLOWSKY), likes his work is of no comfort.
He eventually turns to inhaling gasoline fumes as a way of escaping, but must explain the smell to Maura by lying that it's from his work with remote controlled model airplanes. That ultimately leads to him meeting Denny (JACK KEHLER), an odd sort and model hobbyist who soon befriends the grieving and increasingly high widower.
Wilson's addiction to such fumes means that he can temporarily forget about his mixed urge and reluctance to open what's presumably Liza's suicide note to him. Her mother, Mary Ann Bankhead (KATHY BATES), doesn't want to read it either and it eventually becomes a tattered reminder of what once was. As Wilson's addiction grows more incessant, he tries to come to grips with what's occurred and eventually summon the courage to open that letter.