Adapted from Wilhelm Meyer-Forster's play, a crown prince has a lonely life except for his tutor and at Heidelberg, where he falls in love with a barmaid.
King Karl VII (Gustav von Seyffertitz) welcomes his son Karl (Philippe De Lacy) home as people cheer. The boy is isolated from all but old men and his tutor, Dr. Friedrich Juttner (Jean Hersholt).
Years later Karl Heinrich (Ramon Novarro) passes his high school examination. He wants Dr. Juttner to stay, and they go to Heidelberg.
At an inn Kathi (Norma Shearer) gives Karl flowers and shows him his rooms. Karl sees students eating and cheering Kathi, who drinks a beer. She comes into his room and says she is engaged because her parents like him. A drunk student comes in and invites others. They give Karl a cap, and he says he is Karl Heinrich of Karlsburg. They drink beer and sing.
Karl climbs over a wall and kisses Kathi. They dance and go boating. Dr. Juttner gets a letter saying that Karl must marry Princess Ilse. Karl tells Johann Kellermann (Bobby Mack) that he will make him his major-domo, but he hesitates what he will make Kathi. She tells Karl that she loves him, and Dr. Juttner puts the letter away.
Prime Minister Von Haugk (Edward Connelly) comes to Dr. Juttner. Karl gives Kathi a dress, and they kiss in public. Von Haugk tells Karl that his father is ill, and he must go home. Kathi comes in, and Von Haugk goes out. She sadly helps Karl pack and kisses him goodbye. Dr. Juttner consoles her.
King Karl VII tells his son Karl that he will marry Princess Ilse. The King is dying, and the prince is persuaded not to argue. Karl learns that his father is dead, and he mourns. Kathi puts flowers on the grave of Dr. Juttner.
Von Haugk asks Karl to sign his wedding announcement, and he does so. Johann comes to see Karl, who is glad to see him and gives him a meal. Johann says that Kathi is still waiting for him. Karl imagines going back to Heidelberg and decides to go.
Karl arrives in Heidelberg and learns that the students are gone. Some Saxonians come to greet him formally as king. Kathi sees Karl, and they embrace. She says they each must marry and be happy. Karl says he will always remember her and leaves.
In the final scene King Karl rides in a procession, and someone says, "It must be wonderful to be king."
This romantic drama suggests that a royal life can be
so sheltered that it may be lonely and filled with more duties
than happiness. This is contrasted to the happy years in college