Writer Jan Roelfsema does a trip to the countryside for finishing his novel. He ends up in the former Hostel of the recluse siblings Karl and Anna whose strange behavior appear to be keeping a probably dark secret. During his search for answers he discovers many signs which will draw a horrible picture in his head - about Anna being held as a sex slave or worse. Acting as any brave man in love would do, his attempt to free Anna reveals the much more shocking truth. Anna is in fact a Werewolf whose nightly killing spree was prevented by her loving brother Karl - until now.