A security agent at the White House uncovers evidence suggesting that a ninth Nazi spy successfully infiltrated the United States despite the FBI's capture of the original eight-man sabotage team. Following the interception of the initial group after the attack on Pearl Harbor, the protagonist must navigate the high-stakes environment of wartime Washington D.C. to identify the remaining operative. The narrative follows the agent's investigation as they piece together clues left by a deceased woman and missing explosives. The story operates within a tense, historically grounded framework, emphasizing the paranoia and urgency of the early American home front during the second World War.

Readers frequently highlight the book's commitment to historical accuracy regarding the real-life Nazi sabotage attempts during the early 1940s. Discussion often centers on the author's ability to maintain a sense of urgency as the protagonist races against time to prevent a potential attack. Critics note that the narrative prioritizes procedural detail and the mechanics of intelligence gathering over character-driven subplots. The atmosphere is consistently described as claustrophobic and tense, effectively capturing the anxiety of the era for the reader.