Task: Question Generation
Input (English): Maria and Frieda, recently orphaned identical twin teenage girls, move from Venice to Karnstein in Central Europe to live with their uncle Gustav Weil. Weil is a stern puritan and leader of the fanatical witch-hunting 'Brotherhood'. Both twins resent their uncle's sternness and one of them, Frieda, looks for a way to escape. Resenting her uncle, she becomes fascinated by the local Count Karnstein, who has the reputation of being "a wicked man".Count Karnstein, who enjoys the Emperor's favour and thus remains untouched by the Brotherhood, is indeed wicked and interested in Satanism and Black Magic. Trying to emulate his evil ancestors, he murders a girl as a Human Sacrifice, calling forth Countess Mircalla Karnstein from her grave. Mircalla turns the Count into a vampire.Frieda, following an invitation from the Count, steals away to the castle at night, while Maria covers for her absence. In the castle, the Count transforms Frieda into a vampire, offering her a beautiful young chained victim. Returning home, Frieda threatens Maria to keep covering for her nightly excursions, but secretly fearing she might bite her sister.Meanwhile, Maria becomes interested in the handsome young teacher, Anton, who is initially infatuated with the more mysterious Frieda. Anton has studied what he calls "superstition", but becomes convinced of the existence of vampires when his sister falls victim to one. One night, when Frieda attacks a member of the Brotherhood, she is captured by her uncle and put in jail. While the Brotherhood debates the vampire woman's fate, the Count and his servants kidnap Maria and exchange her for Frieda in the cell. Anton goes to see Maria, not knowing that she is actually Frieda. She tries to seduce him, but he sees her lack of reflection in a mirror and repels her with a cross. Anton rushes to rescue Maria from burning. Maria kisses a cross, revealing her innocence.Weil now listens to Anton's advice on the proper ways to fight vampires, and the two men lead the Brotherhood and villagers to Karnstein Castle to confront the Count. The Count and Frieda attempt to escape, but they are surprised by Weil, who beheads Frieda. Maria is captured by the Count, who uses her as a shield. Weil challenges the Count and is killed, giving Anton the opportunity to pierce the distracted Count's heart with a spear. Anton and Maria are united as Karnstein crumbles to corruption.
Output (English): How is Maria's innocence revealed?