"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. He is about to appear in Vienna, which causes a sensation. 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. She is so impressed with him that she decides that she too will become a dressage rider. After a time the normally unapproachable Cavelli agrees to give her personal tuition. At first their relationship is very friendly, but when he discovers the name of his pupil, Cavelli attempts to distance himself from her. 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. At the same time, however, he also asks her to travel to
London with him the very next day. Irene enthusiastically accepts and goes to her father's to gather her papers. While she is there, she comes across a photograph of Cavelli with her brother. 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. When the general realises from what Irene says in her distress that this is the man who wants to marry her, he fetches his pistol in order to kill him. Only Irene's threat of suicide dissuades him. 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. General von Ketterer accepts the truth of this and he and Cavelli are reconciled. The incriminating documents are burnt and the way stands open for Irene's marriage to Cavelli otherwise Count Werffen. == Background ==