The Four Feathers by A. E. W. Mason

In THE FOUR FEATHERS, British officer Harry Faversham resigns his commission just prior to the Battle of Omdurman for personal reasons, rather than cowardice, but he is faced with censure from three of his comrades, each of whom presents him with a feather, and the loss of the support of his fiancéE, who presents him with the fourth feather. Questioning his true motives, Harry resolves to redeem himself in combat, traveling on his own to the war-ravaged Sudan.