"Carlo Cavelli" is the professional name of a world-famous dressage rider (Rudolf Forster), who always wears a mask in his public performances and whose real name is unknown.

At the dressage competition he comes to the attention of Irene von Ketterer (Angela Salloker), a young woman who after a fight with her mother (Camilla Gerzhofer) has gone to stay with a friend.

This is because his life was totally changed by a duel in which he shot and killed his best friend's son, Franz, Irene's brother (Paul von Hernried), an action the memory of which still tortures him.

Nevertheless, after an interval, he acknowledges his great attraction to Irene and after establishing that his feelings for her are reciprocated, he decides to ask for her hand in marriage.

When she asks her father, General von Ketterer (Hans Homma), about it, he tells her the story of the duel in which Count Werffen, who later called himself Cavelli, killed her brother.

Cavelli visits Irene's father that evening with three friends, who bring with them various documents from which it becomes clear that Irene's brother Franz had been unmasked as a spy and that Cavelli had only set up the duel to spare the von Ketterer family the shame of the otherwise inevitable court martial and execution.

Other parts were played by: Herbert Hübner (Schott); Lisl Kinast (Flori Weidner); Dinah Grace (dancer): Alfred Neugebauer (von Radnigg); and Johannes Roth (clown) The film was produced by the Berlin production company ABC-Film and shot in the Rosenhügel and Sievering Studios of Sascha-Film in October and November 1934.