Guided by a set of “wedding crashing rules,” John Beckwith (Owen Wilson) and Jeremy Grey (Vince Vaughn) can charm their way into any wedding…and into the hearts of every bridesmaid. But that the biggest nuptials of the year, John breaks the rules and falls for the daughter (Rachel McAdams) of the US Secretary of Treasury (Christopher Walken), and Jeremy is left at the mercy of her “stage-five-clinger” sister (Isla Fisher). Being there for his buddy, Jeremy follows ....