Christine Kuehn’s Family of Spies: A World War II Story of Nazi Espionage, Betrayal, and the Secret History Behind Pearl Harbor (2025) is both a personal memoir and a work of historical nonfiction. After receiving a mysterious letter from a screenwriter, the author embarks on a 30-year investigation into her family’s dark past, which her father, Eberhard, and her aunt, Ruth, spent a lifetime concealing. She is horrorstruck to learn that her seemingly ordinary German grandparents, Otto and Friedel Kuehn, were Nazi spies who provided critical intelligence to Japan for the attack on Pearl Harbor. The book explores themes of Facing the Weight of Inherited Guilt, The Seductive Lure of Ambition and Violent Ideologies, and Espionage amid the Fog of War.

Drawing on her background in journalism, Kuehn combines personal memoir with historical investigation, using an interwoven collection of declassified FBI files, military trial transcripts, personal interviews, and private family documents to reconstruct the events that her family tried to erase. The narrative details Otto Kuehn’s rise in the Nazi party and his family’s subsequent activities as amateur spies in pre-war Hawaii, juxtaposing these accounts with historical data on the meticulous operations of Japanese intelligence and the counterespionage efforts of the FBI. By tracing her family’s path from Nazi Germany to their central role in the Pearl Harbor attack, Kuehn examines how personal ambition and historical forces converged to produce a devastating outcome.

This guide refers to the 2025 Celadon Books edition.

Content Warning: The source text and this guide contain depictions of racism, antisemitism, graphic violence, child abuse, death by suicide, illness, imprisonment, violent death, and references to genocide.

Plot Summary

In the winter of 1964, a woman named Ruth flies from New York to Munich. She drives to an apartment in the Bavarian Forest and packs five boxes of family records. Then she and her younger brother, Hans, drive to a field and burn the boxes, erasing their family’s records.

The narrator, Christine Kuehn, grows up in Florida with her father, Eberhard Kuehn (Ruth and Hans’s brother). Eberhard Kuehn is a German immigrant who tells fantastical stories about his childhood but avoids discussing the true details of his past, mentioning only that he lived in Hawaii and fought in World War II, and claiming that his father, Otto, died in a car crash. 

In 1994, Christine receives a letter from a screenwriter who is researching German spies involved in the Pearl Harbor attack and wants to contact Eberhard and his sister, Ruth. Christine recalls that in her only meeting with the mysterious Ruth, her aunt refused to discuss the family, warning Christine, “You don’t need to know about the family, the past, or Pearl Harbor” (16). Spurred by the screenwriter’s letter, Christine and her husband, Mark, research World War II and realize that her grandfather (Bernard Julius Otto Kuehn) was a Nazi spy who gathered intelligence on Pearl Harbor for the Japanese. When Christine confronts her father, he initially denies it but soon begins to recount the family’s dark history.

The narrative shifts to 1915, when a young Otto Kuehn is serving on a German battle cruiser during World War I. When his ship is sunk, he becomes a prisoner of war in Edinburgh for several years. After the war, he returns to Berlin and marries Friedel Birk, a woman with two children, Leopold and Ruth. After his aunt gets in touch and gives him a portion of the family fortune, he loses the money on several failed business ventures but finally succeeds with a coffee-importing business. In 1926, his son Eberhard (Christine’s father) is born. In the late 1920s, Otto begins working for the German navy’s secret police, hunting communists.

Following the 1929 stock market crash, the Kuehn family wholeheartedly embraces Nazism. In 1931, Otto is considered for a high-ranking position in the SS intelligence service. However, Otto loses the opportunity to a rival and takes a different role in the secret police. Later, a different rival frames him for embezzlement, and Otto is forced to return to Berlin to address the false charges. The debacle earns him enemies in the Nazi party, one of whom later arranges for his arrest and execution. Fortunately, Friedel secures Otto’s release just in time. Otto returns home but further endangers his precarious position when he fails to carry out an assassination as ordered during the 1934 “Night of the Long Knives,” (when Hitler orders the assassination of Nazis, mostly Brownshirts, seen as a threat). 

By 1935, Leopold has become a deputy in Joseph Goebbels’s Propaganda Ministry. When he invites Ruth along to a party, she encounters Goebbels and begins an affair with him. (Christine’s research reveals that Ruth’s biological father was a Jewish architect, making her half Jewish.) When this fact comes to Goebbels’s attention, he acts quickly to avoid a scandal under the new Nuremberg Laws, which forbid “sexual relations between [non-Jewish] Germans and Jews” (62). Recognizing the Kuehns’ talents for espionage, Goebbels arranges for them to be sent on a spy mission to Hawaii on behalf of Japan, thereby removing his Jewish lover from Berlin.

In 1935, Otto and Friedel travel to Hawaii and the Far East, temporarily leaving the children in Berlin. Otto signs a lucrative contract with the Japanese naval attaché and meets his intelligence contact, Captain Kanji Ogawa, in Shanghai. As antisemitic laws intensify in Germany, Friedel returns for the children. Ruth and Eberhard arrive in Hawaii first, followed by Friedel and the youngest son, Hans. 

The family begins their espionage work, using Otto’s cover story of studying the Japanese language. They live lavishly, hosting parties for US military officers in order to gather intelligence. Their profligate spending and flamboyant activities attract the attention of the German consulate, which confirms that Otto is a spy. As the Kuehns continue their espionage, Ruth becomes a key asset, using her good looks and elite social life to collect information from naval officers.

On one of the family’s many trips to Japan to meet with their handlers, Ruth encounters Dr. Wilhelm Homberg, a German executive in Japan who also functions as an intelligence contact and payoff man. She soon becomes engaged to him. Meanwhile, Otto establishes a cover business, the Modern Steel furniture company, in order to gain direct access to Pearl Harbor.

In August 1939, the Kuehns’ activities finally prompt the FBI to act on its suspicions and open a permanent office in Honolulu under Special Agent Robert L. Shivers, who immediately begins investigating the Kuehns in earnest. As World War II begins, payments to the Kuehns from Japan stop, causing the family financial trouble. A desperate Friedel travels to Japan to confront Homberg and is infuriated to find her daughter’s fiancé with another woman. She manages to secure a partial payment, then returns to Hawaii and forces Ruth to break off the engagement with Homberg. At age 25, Ruth eventually marries Jacob Carson Moore, an older stockbroker with two children. He knows nothing about the Kuehns’ espionage.

Meanwhile, the FBI’s suspicions grow, but they do not have enough evidence to take action against the Kuehns. Friedel and Ruth open the Kailua Beauty Shop as a front to gather information from the wives of naval officers. When Otto builds a dormer window on their house, Shivers suspects that this is meant for signaling submarines. 

As Otto makes conspicuous contact with the Japanese consulate, Japanese intelligence begins to consider him a security risk and asks for a replacement. The German Abwehr sends double agent Dusko Popov, but his mission is aborted after he warns FBI Director J. Edgar Hoover of an impending attack. The warning is disregarded. In October 1941, Japanese intelligence officer Takeo Yoshikawa visits the Kuehn home, delivers $14,000, and activates Otto for the final phase of the mission to attack Pearl Harbor.

In the week before the attack, Otto is tasked with creating a signaling system to communicate US fleet movements. On December 2, he delivers the simplified plan to the consulate. On December 7, 1941, Japan attacks Pearl Harbor. In the aftermath of the attack, Shivers orders the roundup of a barrage of suspects, and the FBI raids the Japanese consulate, finding partially burned documents—including the telegram detailing Otto’s signal system.

Around midnight, the FBI arrests Otto, Friedel, Eberhard, and Ruth. The family is taken to a detention center and later the Sand Island internment camp. During interrogation, Otto signs a full confession, while Friedel and Ruth admit to nothing. Shivers interviews 15-year-old Eberhard, detaining him as a security risk even though the boy is innocent. In February 1942, Otto faces a secret military tribunal, and Eberhard and Hans are forced to testify against him. The commission finds him guilty and sentences him to be shot by a firing squad.

Otto’s execution is delayed due to legal questions over the tribunal’s jurisdiction. A Supreme Court ruling in a separate case involving German saboteurs clarifies that military tribunals are only appropriate for wartime offenses, so Otto’s sentence is commuted to 50 years of hard labor, and he is sent to Fort Leavenworth. 

Eberhard is released from internment after five months and renounces his family’s Nazi ideology. Friedel, Hans, and Ruth are transferred to an internment camp in Texas. In 1943, Ruth’s husband files for divorce, and with these proceedings, the espionage story is publicly revealed for the first time. In 1944, Eberhard becomes a US citizen and enlists in the army.

In 1945, Friedel, Ruth, and Hans are repatriated to Germany. Meanwhile, Eberhard fights in the Battle of Okinawa, and Leopold is killed in the final Battle of Berlin. After the war, Otto is released from prison in 1948. He meets Eberhard one last time in New York, begging him to return to Germany, but Eberhard refuses. Otto moves to Buenos Aires and later returns to Germany in 1955, where he dies of cancer. Friedel dies of cancer in 1964, after which Ruth burns the family records. Hans, who was severely abused by a foster family after his parents’ arrest in the aftermath of Pearl Harbor, is so traumatized by his childhood that he dies by suicide in 1974. Ruth lives a quiet life in the US, never speaking of her past. Interspersed throughout her description of these events, Christine includes an account of her own journey of discovery, reflecting on the difficulty of her father’s decision to break away from his family. Although dementia eventually frees Eberhard of his traumatic memories, Christine feels that it is vital for her to resist the family habit of secrecy and tell the Kuehns’ story publicly, particularly as events in the present begin to echo those of the past.