At his uncle’s behest, the young Karl-Heinrich, Hereditary Prince of Saxe-Karlsburg, is sent to Heidelberg to study for a year. After a joyless youth in the gloomy, stately Karlsburg Castle, the prince embarks on the most carefree period of his life. He falls hopelessly in love with Käthi, the charming daughter of his landlords. But duty calls: the prince is gravely ill, and Karl-Heinrich must return to assume his duties as heir apparent and future ruler.

Revealing story about the mysterious Nazi organization "Lebensborn," which was intended to serve the SS in pursuing population policy and racial hygiene goals by systematically producing "hereditarily valuable" children. The film depicts an anti-Hitler Knight's Cross recipient with false papers who becomes a witness and victim of relevant events in a Lebensborn home, where 30 enthusiastic BDM girls and a number of SS hooligans and frontline soldiers have just moved in to "give the Führer a child."