Tom Wall, an American soldier wounded while fighting with the Allies in Crete, wakes up in a London hospital. Physically weakened and suffering from combat fatigue, Tom is aware only of a burning need to find his brother, a diplomat also in London. But British Intelligence has other ideas. They want Wall to help secure a national asset -- the Double Cross System, an intelligence operation now at risk from a German masterspy. Amid the bombsites and blood-stained alleys of blacked-out London, Tom pursues a quest whose goals are constantly shifting, in pursuit of an enemy whose identity is ever changing. Meanwhile a Japanese war fleet is steaming towards Pearl Harbor ...