During the height of the First World War, two young British soldiers, Lance Corporals Schofield and Blake, are given a seemingly impossible mission. In a race against time, they must deliver a message deep within enemy territory that will stop 1,600 men, including Blake's own brother, from walking straight into a deadly trap. If they fail, it will result in a massacre at the hands of the German forces.

The perilous journey takes the soldiers over the treacherous no man's land and through the ruins of the French countryside, devastated by the war's brutalities. They encounter various obstacles, from booby traps to the psychological toll of the landscape littered with the dead. With time running out, the two young men must use every ounce of their courage and determination to navigate through the dangerous terrain and deliver the message that could potentially save thousands of lives.