It is April 6, 1917, and the most powerful nations in the world are embroiled in a war the likes of which humankind has never seen. An aerial reconnaissance team has noticed that the German army is in the middle of a tactical withdrawal from the Hindenburg Line. However, British forces stationed there believe them to be retreating, not knowing of their oppositions true intentions to wipe them out with artillery. The field telephone lines have been severed, so the only way to deliver this valuable information is for it to be conveyed in person. General Erinmore sends two young soldiers, Will Schofield and Tom Blake, to deliver the message to Colonel Mackenzie, who leads the Second Battalion of the Devonshire Regiment. The fate of 1,600 men hangs in the balance.