A reluctant speaker at a pre-Christmas elementary school assembly, FBI Special Agent Lucas Shaw feels the eyes of hundreds of children pleading with him for protection when South Mountain Militia storms the building. Scrambling against a ticking clock, Lucas must find a way to get the children and faculty to safety, a daunting task for one armed federal agent against a small army of gunmen. As if the pressure of his task isn't bad enough, his day is about to get even worse. Fighting for her life when captured by a gunman, Lexie North manages to escape only to collide with Lucas - a man who has every reason to hate her. With danger closing in on them, rescuing the hostages and ultimately their own survival depends on their ability to work together. But can they put aside their past to do it?.