Daniel Ford works as a nighttime taxi driver in London; a mentally unstable passenger confesses a plan to murder his fiancée at the end of his ride.

A young pilot, fresh out of training, is called to join a Flight while they wait for the call to scramble. Throughout a single day, he witnesses the skies of southern England filled with deadly dog fights, and after every exhausting battle the men return to their dispersal hut, only to find another of their number missing. Unwilling to surrender, the pilot and his comrades unite to take to the skies once more, determined to defend not only the airfield, but their entire country.