It's 1943, and nearly-12-year-old George and his older brother Jack are spending a restless wartime summer in Whitby, Ontario, where their mom is working at a munitions plant while their dad is off fighting the Germans. One afternoon, the boys stumble across Canada's top-secret spy camp-and so begins an exciting and terrifying adventure as George and Jack get caught up in the covert activities of Camp X. Fascinated by Camp X and its secrets, the boys begin to suspect local townspeople of being spies. Is the police chief keeping tabs on people for enemy purposes? Is Jack's boss at the newspaper really amassing information for sinister reasons? Unable to resist the camp's allure, the boys keep going back to find out more details of what's going on-they even meet William Stephenson, the Man Called Intrepid himself. They also attract the attention of a very sinister character, someone who is determined to use George and Jack's knowledge against the Allies, no matter the consequences . . . or the casualties.

The thrilling sequel to Camp X, winner of the Silver Birch Award Jack and George have barely recovered from their ordeal in Camp X when they are relocated to Bowmanville, Ontario, where their mother has been offered a clerking job in a prisoner of war camp holding the highest ranking German officers. Soon the boys are offered the after-school job of delivering the camp's mail, and Canadian agents ask them to keep their eyes and ears open for possible escape plans. For, as the boys are told, it is a matter of loyalty to their homeland that the German prisoners must try to escape, even if it costs them their lives—and the lives of two boys in the wrong place at the wrong time.

It’s been months since brothers Jack and George’s adventure in Camp 30, where they’d been sent to spy on the high-ranking German prisoners of war. Now they’re hoping that life will return to normal. But they’re proved terribly wrong when their mother is kidnapped by three thugs who seem to know all about the boys’ pasts. Before they know it they’re on a terrifying new adventure back to Camp X to unearth a buried stash of gold, without which they’ll never see their mother again.

Jack and George have assumed new identities and are back at work as special operatives, keeping an eye out for suspicious activity at an ammunitions plant. They don't have to wait long before they uncover a plot by German spies to blow up the plant and everyone in it! It's up to the quickthinking boys to find a way to stop them and stay alive while doing it ...

George and his family have been relocated to Bermuda in the hope that the Nazi agents who’ve been trying to kill them lose the scent and think them dead. But trouble is never far behind George and Jack, and they soon find themselves in the face of danger yet again. Even though the entire family is now working for Little Bill and his team of spies on the island, the brothers still have their share of secret missions, seeking to foil Nazi conspiracies that would put the lives of thousands of people in jeopardy, including their own ...

Having successfully foiled a Nazi plot to kidnap one of the British Royal Family, brothers Jack and George are on the move again—this time to England. The boys and their parents are travelling aboard a merchant ship that’s part of a convoy carrying supplies and troops to the battlefields of Europe at the request of the royal family, who wishes to thank them for rescuing Princess Louise. Crossing the Atlantic is challenging enough … but when the destroyers attached to their convoy torpedo a U-boat, events take another very surprising turn. The U-boat was transporting a secret: a secret that Jack and George’s mother is now entrusted with … and a secret that the Nazis will kill to protect. When the family comes ashore in England, they’re whisked off to Bletchley Park, the hub of the British spy network, so that they can help to decipher it. True to form, Jack and George soon discover a plan to strike at the heart of the British war effort by sabotaging British intelligence. Will they be able to successfully foil another deadly Nazi plot? In a desperate race against time, Jack and George know that the fate of the whole war effort—and of their family—hangs in the balance …