Please answer the following question: Extract the answer to the following question from the movie plot. If the question isn't answerable, please output "Can't answer". Question: What is Heinrich thwarted by around Dora's neck? Title: Vampire Circus Movie plot: Count Mitterhaus [Robert Tayman] was a vampire, preying on the children of the town of Stetl. With the death of one more child, the people became sufficiently enraged that they stormed the Count's castle and drove a stake through his heart. With his dying breath, Mitterhaus vowed, "Your children will die to give me back my life." Seven villagers went in, four came out -- Professor Albert Mueller (whose wife Anna had become the Count's willing consort), the Burgermeister, Dr Kersh, and Herr Hauser. Just as the castle is consumed in flames, the Count whispers to Anna, "Tell Emil. He will know what to do."Fifteen years later: The town of Stetl is dying, literally. A plague is slowly killing the people, although some believe it is the Count's curse at work. At any rate, neighboring villages, afraid that the plague/curse may spread, have placed roadblocks around Stetl, and they vow to shoot anyone attempting to leave or enter the town. Dr Kersh [Richard Owens] is among those who believes it to be a disease not a curse, and he plans to sneak out of the town and bring back knowledge and medicines from the city. With his son Anton [John Moulder-Brown] acting as a decoy, Dr Kersh manages to get away. Before his father leaves, Anton reminds him to find his girlfriend Dora Mueller [Lynne Frederick], the daughter of Professor Mueller [Laurence Payne] and tell her not to come back. Unbeknown to them, Dora is already planning to sneak through the roadblocks in an attempt to get back to her father and to Anton.Somehow, the Circus of Night manages to make it through the roadblocks. Tricks, performances, dancers, aerialists, wild animals -- the people of Stetl are, at least, to be entertained in their misery. But this is no ordinary circus. Serena [Serena], for example, dances totally nude, except for the tiger stripes on her body, aerialist twins Helga [Lalla Ward] and Heinrich [Robin Sachs] turn into owls as they soar through the air, and when the panther jumps up, he comes down in the body of Emil [Anthony Corlan], who...
A:
Her cross