A nameless, pill-popping drifter girl steps off a bus and into a New Jersey neighborhood bar owned by two middle-age brothers, Jimmy & Victor. She quickly befriends older brother, Victor––a good-natured lummox whose mind was affected by a childhood accident. The mysterious "Girl" soon upsets the delicate balance of the brothers' lives while bringing both trouble and new life into their resigned world and town.

Set on an island off the coast of New England in the summer of 1965, Moonrise Kingdom tells the story of two twelve-year-olds who fall in love, make a secret pact, and run away together into the wilderness. As various authorities try to hunt them down, a violent storm is brewing off-shore – and the peaceful island community is turned upside down in more ways than anyone can handle.