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.
| Actor | Role |
|---|---|
 Christian WolffErbprinz Karl-Heinrich | Erbprinz Karl-Heinrich |
 Gert FröbeDoktor Jüttner | Doktor Jüttner |
 Sabine SinjenKäthi | Käthi |
 Ernst Stahl-NachbaurFürst von Sachsen-Karlsburg | Fürst von Sachsen-Karlsburg |
 Heinrich GretlerGastwirt Rüder | Gastwirt Rüder |
 Rudolf VogelKammerdiener Lutz | Kammerdiener Lutz |
 Walter BluhmDiener Schölermann | Diener Schölermann |
 Siegfried SchürenbergStaatsminister Haugk | Staatsminister Haugk |
 Tilo von BerlepschKammerherr von Metzing | Kammerherr von Metzing |
 Harry MeyenGraf Detlev von Asterberg | Graf Detlev von Asterberg |
| WWolfgang EichbergerKammerherr von Feldbach | Kammerherr von Feldbach |
 Hannelore ElsnerHelene, Serviermädchen | Helene, Serviermädchen |
 Gerd FrickhöfferKammerherr von Breitenberg | Kammerherr von Breitenberg |
 Walter JanssenHofmarschall im Schloss Karlsburg | Hofmarschall im Schloss Karlsburg |
| AAnneliese WürtzFrau Rüder | Frau Rüder |