Sam Cahill (Tobey Maguire) is a successful military man, cherished husband of the beautiful Grace (Natalie Portman), and a loving father to their two daughters. His younger brother Tommy (Jake Gyllenhaal), is the exact opposite - recently released from prison and known for his careless ways; Tommy has always been the black sheep of the family. But when Sam is sent on a mission to Afghanistan, the balance between the two brothers changes forever. During the mission, Sam goes missing in action and is presumed dead, forcing Tommy to undergo a positive transformation. Tommy assumes the role of the noble brother, the caring uncle and the good, responsible son. While mourning Sam, Grace is comforted by Tommy's presence and slowly their mutual sympathy turns into something more intimate. But when Sam comes home, traumatized after being held prisoner in Afghanistan, the two brothers and the woman they both love will have to face the consequences of their explosive love triangle.