Task: Question Generation
Input (English): Professor Abronsius and his assistant Alfred arrive to a small distant village in Eastern Europe in a hope to prove their theory that vampires really exist. Alfred falls in love with a beautiful girl, Sarah, who gets attacked and kidnapped by a vampire Count von Krolock, and he decides to rescue her out of the Count's castle whatever it takes.Professor and Alfred move to the castle and are very friendly received by hospitable Count von Krolock, who offers them to stay there as long as they like, but doesn't mention a ball next night, where his friends come to drink their blood and make new vampires out of them.They spend the next day in attempts to find and kill Krolock, but don't succeed. They lose their luggage with weapons like garlic and crucifix, and learn about the ball.Alfred finds Sarah, who is still a human; she does not want to escape right now, losing the unique possibility to wear a great dress for a real ball. The three of them stay for another night.Krolock's son Herbert falls in love with Alfred and tries to bite him. Alfred rescues himself and the professor in a tower. The Count meets them there to inform, that they will become vampires tonight and will spend their endless lives in the castle. Professor Abronsius is supposed to be Count's companion and Alfred Herbert's boyfriend.They escape from the tower and go to the ball to rescue Sarah. This time they succeed and finally leave the castle. They don't know, that Sarah has already become a vampire. She bites both of them.
Output (English): What were the professor and Alfred trying to prove?