After a devastating global nuclear and chemical war Britain is split in two: the war wasteland in the South and the surviving North. Thousands of refugees from the south are trying to migrate up north where civilised life is still possible. However, these people are carrying a deadly virus and the military is protecting the north from them. A disciplined captain Thomas has lost everything but his fellow soldiers who have to kill anyone approaching from the south. A new recruit Landon however is unable to do it and Thomas is tasked with toughening him up. One extraordinary day Thomas himself is faced with the dilemma of following his heart or orders.