Jack and the German Spy — Bernard Ashley

It's 1939 and the war's beginning. Everyone's afraid of spies.
When Jack tumbles off the Kent train with the other wartime evacuees from London, no one in the village wants to take him in. Then Lady Ashwell patriotically sweeps him off to the Hall, where Jack learns how to hold a knife and fork and her son Clive learns how to fight dirty â€" and when events in the night turn nasty, the boys team up to unmask a sinister enemy.