Cheyenne (Sean Penn) is a former rock star who still dresses like a Goth. Now 50, he relives the days of superstardom with young fan and best friend Mary. Living off his royalties he rattles around his grand Dublin mansion until the death of his estranged father calls him to New York. Reunited with his family, Cheyenne discovers a secret that will send him across America. On a journey through the Midwest, full of surreal encounters with an eclectic mix of characters from New York socialites to ethical gun-shop owners, Cheyenne is on the road trip of his life.