Derek and his friends, living outside of London during World War II, find plenty of opportunities to explore bomb craters, collect shrapnel, and identify the fighter planes that fly overhead. When a bomb hits close to school, causing classes to be canceled, the boys are overjoyed: They can spend the day building their secret camp. But when their work on the camp is sabotaged, a tough neighboring gang is to blame. A violent clash with the rival gang - followed by a long night of bombing close at hand - change forever Derek's feelings about the war.