Since university, confirmed bachelor Ronny (Vince Vaughn) and happily married Nick (Kevin James) have been through thick and thin. Now partners in an auto design firm, the two pals are vying to land a dream project that would launch their company. With Ronny's girlfriend, Beth (Jennifer Connelly), and Nick's wife, Geneva (Winona Ryder), by their sides, they're unbeatable. But Ronny's world is turned upside down when he inadvertently sees Geneva out with another man and makes it his mission to get answers. As the amateur investigation dissolves his world into comic mayhem, he learns that Nick has a few secrets of his own. Now, with the clock ticking and pressure mounting on the biggest presentation of their careers, Ronny must decide what will happen if he reveals the truth to his best friend.