In 1941, Darwin is bombed, and the war against the Germans and the Japanese gets alarmingly close. While those in the area are raising money for the war effort with backyard concerts, the kids on Bolton Road have their own ideas about how to help out. Notices around the town warn that loose talk kills. Are spies passing information to the enemies right under their noses? Mable convinces Nancy, Janet, Fred and Lennie that catching spies is the best way to do their part. But will their efforts catch the traitors...or make the kids targets?