Herschel Schwendemen and Lev Wycoff are on the hunt for the heirs of Adolf Hitler, and they've found them - a little boy named Erich, and his great grandfather Ingolf Mayr, who is the son of the worst dictator Germany has ever known. Along with Kata, Erich's mother, and Ingolf's granddaughter, the two Mossad agents - though one is retired - listen to Old Ingolf tell the story of how he came into being.
Elfriede Mayr is a young, beautiful blonde working for Heinrich Hoffman in the early days of the Nazi Party when she meets Adolf Hitler. Despite the odds, Elfi (as she's known) falls head over heels in love with the older, strange acting man. While her sister Gretchen is staunchly against the relationship, Elfi has an affair and becomes pregnant even while outside agitators, like Geli Raubal, plague the relationship.
Once little Ingolf arrives and Eve Braun steps into the picture, things change for Elfi. Life becomes a hardship, even with the Nazi Party's donations from millionaires. Things come to a head with Geli's 'suicide'. Elfi realizes what a dangerous man Adolf truly is, and breaks ties with him. She is left to raise Ingolf on her own but he grows into a good kid with morals, though he knows who his father is.
Ingolf helps a Jewish doctor - Aron Eisenberg - even though he should be in school. He does this until the day Martin Bormann comes after him, and then he is aided by the good doctor to escape Germany, with the help of an organization that helps Jews cross the border into neutral Switzerland. Ingolf takes the son of an imprisoned Jewish couple there, but cannot leave himself. He stays behind, joins a youth resistance group, and launches attacks against the Nazis until the SS finally comes for him.
Arrested and taken to Berlin, where his ailing father hides in his bunker, Ingolf finally sees Adolf for only the second time in his life. There is an explosive confrontation that involves a drugged Eva Braun, and when it's over, Ingolf must leave the bunker in a hurry. He flees to a town where his mother is hiding out, only to find the house vacant and bloody. Then Adolf Eichmann appears to whisk the youth away, out of the hands of the Allied forces marching into Berlin.
Ingolf winds up in Argentina before coming to America, where he makes his final home. At his story's conclusion, the Israelis voice an offer that Kata is more than happy to refuse. In the end, the Mossad agents leave without incident, and the Mayersons - as they are known - are left to live their lives in the middle-class comfort of suburban America.