A young Jewish boy, Solomon (Marco Hofschneider), undergoes circumcision at a tender age. As the years pass, on the momentous day of his Bar Mitzvah, tragedy strikes when Kristallnacht unfolds, resulting in the loss of his sister. In the aftermath, Solomon, along with his parents—Klaus (Klaus Abramowsky) and Michèle (Michèle Gleizer)—and his two brothers, Isaak (René Hofschneider) and David (Piotr Kozlowski), are compelled to flee to Lodz, Poland.
As the German forces invade Poland, Solomon's father devises a plan to send him and Isaak away in a desperate hope for their safety. Sadly, the brothers become separated amidst the chaos. Solomon is ultimately saved by Soviet soldiers and taken to a Soviet orphanage in Grondo, where he eventually becomes a member of the Soviet Communist Union of Youth.
However, danger looms again when German forces assault the orphanage, forcing Solomon to flee again, ultimately leading to his capture by German soldiers. Utilizing his fluent German skills, he successfully convinces them that he is a German named Josef Peters. Adopting this new identity, Solomon, now calling himself Josef or Jupp, identifies Stalin's son to gain favor with the Germans.
During his time in this new guise, he forms a bond with Robert (André Wilms), a gay German soldier who discovers Solomon's true heritage when he sees his circumcision. Robert, in a show of loyalty, vows to keep Solomon's background a secret. However, during a fierce combat with Soviet forces, Robert and two other German soldiers lose their lives, leaving Solomon to navigate his perilous situation alone.
Desperate, Solomon attempts to surrender to the Soviet soldiers but finds himself caught in a surreal circumstance where the Germans mistake him for a hero, ultimately sending him to a Hitler Youth school. On the train heading to the school, an intimate encounter occurs between him and another woman. Interestingly, it's revealed that Solomon shares a birthday with Hitler, complicating his identity further.
At the Hitler Youth school, Solomon is heralded as a war hero. He is assigned to room with Gerd who quickly becomes a close friend. Moreover, Solomon finds himself infatuated with Leni (Julie Delpy) — a fellow student. However, his affection is complicated by the necessity to keep his Jewish identity concealed, preventing him from having a romantic relationship with her. The school's process of measuring students for racial purity erroneously labels Solomon as Aryan despite his true lineage.
During an annual medical examination, Solomon cleverly fakes a toothache to evade being undressed, fearing exposure. Tensions mount when an argument erupts with Leni, during which he reacts by striking her after she insults Jews. Leni, in turn, calls him a limp dick, leaving their relationship strained. Some time later, upon visiting her mother (Halina Labonarska), Solomon learns that Leni is pregnant with Gerd's child, impacting him deeply. He confesses his true identity to Leni's mother, who promises to keep his secret.
However, his precarious situation escalates when he is summoned to a police station regarding a paperwork issue, during which he must provide his Certificate of Purity. When asked about the certificate, he deceitfully claims it is still in Grondo, aware that the commander intends to investigate further. Fearing his imminent exposure, fate intervenes when the building is bombed, tragically resulting in Gerd's death.
As a chaotic battle for Berlin ensues, Solomon ultimately surrenders to the Soviet army, courageously revealing his true identity as a Jew. Initially met with disbelief, the situation turns when Isaak, recently freed from a concentration camp, identifies him. In a twist of fate, Solomon and Isaak are liberated, paving the way for their journey to Palestine, a land that later transforms into Israel.
