Christine Kuehn describes her father, Eberhard, as a lovable but imposing German immigrant who tells fantastic, untrue stories of wrestling alligators or rescuing abandoned toddlers instead of discussing the truth of his past. He treats these tales as fact and offers only vague, telegram-like details of growing up in Hawaii and fighting in World War II and Korea. He briefly mentions his first marriage and maintains that his father was a naval officer who died in a car crash. Christine’s mother, who died of cancer in 1982, never revealed any family secrets.

Christine recalls that in June 1976, a tall man appeared at their door. Eberhard stepped outside and warned him not to mention his family because his household does not know. The visitor was his estranged eldest son from his first marriage. Christine later learned that Eberhard’s first wife used his family’s Nazi past against him in arguments, causing him to become permanently guarded.

In the summer of 1994, now married with three children and living in Maryland, Christine receives a letter from a California screenwriter researching Pearl Harbor. He claims that her grandfather, Otto Kuehn, was involved with the Nazis. Her husband, Mark, dismisses the letter as a mistake, and Christine plans to tell the screenwriter that he has the wrong family.

Christine sleeps poorly that night, plagued by visions of Pearl Harbor. She remembers meeting Aunt Ruth once in 1987. 

On that day, Ruth offered minimal information about the family, and when Christine asked about her grandparents, Ruth grew agitated and warned Christine against investigating the family’s past. She mentioned Pearl Harbor, then refused to say any more, telling Christine to ask her father.

After the visit, Christine called Eberhard, who again provided only vague details. He claimed that his mother, Friedel, died in Germany and his father died of cancer there; this contradicted his earlier claim that his father was a naval officer who died in a car accident. Christine noticed the discrepancy but let the matter drop for seven years—until the screenwriter’s letter arrived.

Christine and Mark drive to Borders Books to research World War II. Flipping through various histories, Mark finally finds Otto Kuehn listed in the index of At Dawn We Slept: The Untold Story of Pearl Harbor (1981). The book describes Otto as a Nazi spy sent to Oahu in the mid-1930s with his wife, Friedel, and their children. The Japanese paid him $2,000 monthly to spy on Pearl Harbor in preparation for their eventual attack.

Christine discovers mentions of Otto in multiple books. One claims he used his youngest son, Hans—dressed in a sailor suit—to tour ships and gather intelligence. Another asserts that on December 7, 1941, Ruth and Otto signaled Japanese bombers from their home’s dormer window, directing the attack. Still others describe FBI agents bursting in to find the family stuffing cash into suitcases before a planned submarine evacuation.

Shaken, Christine buys the books and returns home. She later visits the Mormon Temple’s genealogy center, where records confirm that Eberhard is Otto’s son. She calls her father, who initially denies everything, then calls back sobbing uncontrollably. Through his tears, he confirms the accusations are true.

In winter 1915, a 19-year-old Otto Kuehn serves aboard the German battle cruiser SMS Blücher, enduring harsh conditions and scarce food. At the Battle of Dogger Bank in January, the Blücher is ambushed and sunk by British forces. One of only 260 survivors, Otto is taken to Edinburgh Castle and held as a prisoner of war.

The author relates that Otto was born in 1895 into a wealthy Berlin family. His father, Karl Bernhard Kuehn, was a respected chemistry professor. Otto had two brothers: Martin, three years older, and Bernhard, four years younger. Their mother, Elisabeth, died of cancer in 1912. After her death, Otto struggled with his studies and enlisted in the navy in 1913, seeking adventure.

During World War I, Martin was killed while fighting in Serbia, and Bernhard was sent to fight in France. Heartbroken and alone, their father Karl died of cancer while Otto was still imprisoned in Edinburgh. After the war, Otto returned to his hometown of Stettin to learn that his aunt, Elsa, had sold the family estate and moved to Sweden, taking all the family money with her.

Penniless after the war, Otto and Bernhard move to Berlin, where their Aunt Martha provides housing and pays for their university tuition. Bernhard thrives in medical school, but Otto drops out after a year. He meets Friedel Birk, age 28, who has two children from previous relationships: Leopold, born after her first fiancé abandoned her, and Ruth, born after her relationship with an architect ended. Before meeting the architect, she was also engaged to a German air force pilot who was killed in World War I. Otto and Friedel fall in love.

Otto unexpectedly receives a large inheritance from Aunt Elsa—$50,000, two houses, and bonds. He takes a huge loss when he invests heavily in a freighter that runs aground and is sold for scrap. Otto marries Friedel in 1920, adopting Leopold and Ruth. His next business venture, a sparkling water company in Stettin, also fails, forcing him to work as a dairy inspector to make ends meet. He then starts a coffee-importing business in Berlin, which finally succeeds. In 1926, Eberhard is born.

Meanwhile, Adolf Hitler is building the Nazi Party. Joseph Goebbels arrives in Berlin in November 1926 and takes charge of the Nazis there, launching violent street battles between Nazi Brownshirts and communist groups. Around this time, Otto becomes bored with his coffee business and joins the Reichsmarine’s secret police in 1928, hunting communists. The work excites him and allows him to hone his espionage skills.

The 1929 US stock market crash devastates Germany, causing unemployment and poverty to spread. Hitler capitalizes on the chaos, holding rallies across Germany. In summer 1930, Otto takes Leopold to a rally in Kiel, where Hitler delivers a fiery speech promising prosperity, expansion, and the restoration of German pride. Otto is mesmerized and joins the Nazi Party the next day. Leopold enlists in the Sturm Abteilung (the Storm Troopers, or SA), while Friedel joins the Nazi women’s auxiliary and Ruth joins the Bund Deutscher Mädel (BDM), the girls’ section of the Hitler Youth.

In the 1930 elections, the Nazis dramatically gain traction, receiving 6.4 million votes and becoming Germany’s second-largest party. As a member of the SA, Leopold participates in violent attacks on Jewish businesses and political rivals, often returning home bloodstained to describe his exploits. Five-year-old Eberhard witnesses these accounts firsthand.

In August 1931, Otto is summoned to Munich to interview with Heinrich Himmler for head of SS counterintelligence. His rival for the position is Reinhard Heydrich. In an impulsive moment of generosity, Otto loans Heydrich 100 marks for the train ticket to the interview. Ironically, Heydrich ends up getting the job instead of Otto, who goes on to fill a different position in the Nazi secret police.  (Heydrich later becomes the architect of the Holocaust, ordering the construction of Dachau, the first concentration camp, and leading the conference on the so-called “Final Solution”: the extermination of the Jewish people.)

By early 1933, Otto has settled back into routine in Berlin, his coffee business thriving. But Schmidt, a Nazi official whom Otto had accused of immorality in Altona, arrives to seek revenge. One morning, men burst into Otto’s office and drag him to a police cell. Schmidt has arranged for Otto to be driven to Hamburg and executed along the route.

Friedel learns of the arrest from a police director friend, who warns her to free Otto by morning. She contacts Leopold, who reaches the regional Nazi leader and secures a release letter from a Gestapo agent. Otto is freed hours before his planned murder. Four months later, the Gestapo agent who wrote the release letter is shot and killed as punishment.

On January 30, 1933, Hitler becomes chancellor. He quickly consolidates power using the Reichstag Fire as pretext to arrest communists and suspend civil liberties. In July 1933, all rival political parties are abolished. In August 1934, Hitler combines the offices of chancellor and president, becoming Führer.

In June 1934, during the Night of the Long Knives, in which Hitler orders the murders of Nazis deemed a threat, Otto is ordered to assassinate a high-ranking SA member. He sneaks into the man’s house and holds a Luger to his face, but when the terrified man offers him 30,000 marks to escape, Otto accepts. He emerges richer but is now in a highly vulnerable position, for if his treachery is discovered, his status in the Nazi party will count for nothing.

In early 1935, Leopold brings 19-year-old Ruth to one of Joseph Goebbels’s galas in Berlin. Goebbels delivers a fiery antisemitic speech, then spends the evening with Ruth. Despite being married with children, Goebbels is notorious for having affairs and soon begins a relationship with Ruth, showering her with privileges and perks.

The author analyzes Ruth’s past. In the poverty of Ruth’s youth before Friedel married Otto, the girl had grown up amid constant upheaval, moving repeatedly between cities, and this pattern left her searching for stability. At age 15, she joined the Bund Deutscher Mädel, the Nazi girls’ youth organization, which indoctrinated young women into Nazi ideology and trained them to become wives and mothers for the Reich. With her family deeply involved in Nazism, Ruth clung to the movement as one of her only social connections.

In 1997, Christine discovers a 1952 letter among her research materials and realizes that Ruth’s biological father was not Otto but Martin Punitzer, a Jewish architect who fled to Chile in the 1930s. This means that Ruth was “half Jewish.” She surmises that Goebbels must have discovered Ruth’s heritage. With the Nuremberg Laws about to make relationships between non-Jewish Germans and Jewish people illegal, his affair with a “half Jewish” woman would have been a devastating scandal, so Goebbels needed Ruth to disappear.

In 1935, the Kuehn family disappears without notice. Otto’s brother Bernhard later recalls that they left without goodbyes or warning. Goebbels has devised a solution for his Ruth problem: The Japanese need “Caucasian” spies in Hawaii. He sees an opportunity to eliminate evidence of his affair while serving the Reich.

Otto meets with Japanese naval attaché Captain Tadao Yokoi in Berlin and signs a contract worth $2,000 monthly plus a $6,000 yearly bonus—equivalent to $680,000 annually today. Otto and Friedel leave for Hawaii first, leaving the children with Leopold in Berlin. Ruth stays hidden to avoid Goebbels and the escalating violence against Jewish people. They arrive in Hawaii in spring 1935 and are enchanted by the lush landscape of Waikiki Beach.

Otto travels to Tokyo and Shanghai to meet his Japanese handlers, including Captain Kanji Ogawa, who grills him about his experience in the Nazi secret police. Impressed, the Japanese deposit $20,000 in the Kuehns’ account. Otto returns to Hawaii and begins cultivating Navy contacts, claiming that he is learning Japanese so that he can teach it at a German university.

As violence in Berlin intensifies through the summer 1935, Friedel returns to Germany. On September 15, the Nuremberg Laws strip all Jews of their civil rights. Ruth and Eberhard travel across the United States and depart for Hawaii on November 14, the same day the Nuremberg Laws take effect. 

By April 1936, the entire family—minus Leopold, who stays in Berlin—is reunited in Hawaii. They rent a house with ocean views, and more funds from Japan continue to arrive. German consulate officials in Hawaii investigate Otto, learn that he is a spy protected by Goebbels, and consider him a dangerous man. The FBI begins intercepting communications about a German operative in Honolulu who is meant to establish a steel furniture business as a cover. The pieces are in place for Japan’s eventual attack on Pearl Harbor.