Operation Overlord — Francis Moss

Royal Naval Lieutenant Commander Lawrence Collins takes his son Tommy with him to Southampton for Most Secret work in the days before the Normandy invasion. Tommy is sometimes wrong about things, but he usually-make that always-thinks he's right. Exploring Southampton, Tommy meets Annike, a Kindertransport Dutch girl whom he mistakenly thinks is a German spy. Despite this comedy of errors beginning, Annike and Tommy become friends and on the day before the Allied invasion of France, they risk their lives and discover Nazi spies plotting to reveal the invasion plans.