Straight-arrow policewoman Cooper (Reese Witherspoon) is excited and thrilled about her next assignment. Her task is to escort Daniella Riva (Sofía Vergara), a wisecracking Colombian beauty, from San Antonio to Dallas so both she and her husband can testify against a drug lord. Plans go awry when Mr. Riva gets ambushed, leaving Daniella a widow. Cooper and her witness must now use their wits to escape from crooked cops and murderous gunmen, while not killing each other in the process.