The First World War reached its peak in spring 1917. While the weakened German troops are withdrawing on the western front, the British have an advantage, but find themselves in a predicament. To save the lives of 1,600 compatriots, British soldiers Schofield (George MacKay) and Blake (Dean Charles Chapman) are dispatched to prevent another unit from being killed in an ambush.
The mission seems to be an almost hopeless race against time, across hostile territory. But not only is the life of hundreds of unknown comrades at stake, but also that of Blake’s brother, who is in the other unit.