Friend Or Foe by Michael Morpurgo

Two young boys evacuated from London during the Blitz are sent to the countryside, where their childhood friendship is tested when they encounter a wounded enemy airman; faced with fear, duty and compassion, they must decide whether to protect him or turn him in, and the choice forces them to confront the blurred lines between friend and foe and the human cost of war as one of them later recalls the experience.