France, May 1940. Seated in the cockpit of his Hurricane, Sergeant George Yeoman — young, eager, and innocent in the ways of war — is on his way to join his first operational squadron. Meanwhile, the German Panzers advance unchecked through the Ardennes, and as the allied bombers plead to strike at them, the Luftwaffe is already set to launch a decisive blow. Disaster beckons and Yeoman and No. 505 Squadron soon find themselves courting death in a series of increasingly desperate sorties as the allied army begins its retreat towards Dunkirk. There are only a handful of them against the might of Hitler's war machine, and with each sortie the ranks of the Squadron grow ever more depleted. The odds stacked against them are hopeless…