The Strange Case of Dr. Jekyll and Miss Osbourne

It's the engagement party for brilliant young Dr. Henry Jekyll and his fiancée, the beautiful Fanny Osbourne, attended by various pillars of Victorian society. But when people are found raped and murdered outside and ultimately inside the house, it becomes clear that a madman has broken in to disrupt the festivities - but who is he? And why does Dr. Jekyll keep sneaking off to his laboratory?