Marianne Danielle, a young French schoolteacher en route to take up a position in Transylvania, is abandoned at a village inn by her coach driver. Ignoring the warnings of the locals, she accepts the offer of Baroness Meinster to spend the night at her castle. There, Marianne sees the Baroness's handsome son, Baron Meinster, who is said to be insane and kept confined. When she sneaks into his quarters to meet him, she is shocked to find the Baron chained by his leg to the wall, and when he tells her that his mother has usurped his rightful lands and pleads for her help, she agrees to steal the key to his chain from the Baroness' bedroom.