Extremely shy Lars (Ryan Gosling) finds it impossible to make friends or socialize. His brother (Paul Schneider) and sister-in-law (Emily Mortimer) worry about him, so when he announces that he has a girlfriend he met on the Internet, they are overjoyed. But Lars' new lady is a life-size plastic woman. On the advice of a doctor (Patricia Clarkson), his family and the rest of the community go along with his delusion.

In Vietnam in 1970, Captain Willard (Martin Sheen) takes a perilous and increasingly hallucinatory journey upriver to find and terminate Colonel Kurtz (Marlon Brando), a once-promising officer who has reportedly gone completely mad. In the company of a Navy patrol boat filled with street-smart kids, a surfing-obsessed Air Cavalry officer (Robert Duvall), and a crazed freelance photographer (Dennis Hopper), Willard travels further and further into the heart of darkness.