In Victorian London, the police are looking for an unknown man wearing a top hat and dark cloak as the perpetrator of what have been coined the Whitechapel Murders, the victims knifed to death being young women of ill-repute. Concurrently, research scientist Dr. Henry Jekyll feels compelled to document anecdotally his latest research in case something happens to him. A virologist working on an antidote to cure a number of viruses, he decides to change his field of research on an off the cuff comment by friend and mentor, Professor Robertson, saying that such a cure-all would take years to develop, longer than Dr. Jekyll's lifespan. So Jekyll changes his research to finding the answer to eternal life so that he can live long enough to cure the world of its viruses. In early experiments, he narrows his research to the differences between the sexes and that females have a longer lifespan than males, early experiments on insects increasing that lifespan of males by a factor of three. The two problems are: he needing female organs to advance his research to humans, and exhausting the supply of deceased females in morgues, he turns to killing himself for the greater good, hence he being the Whitechapel Murderer; and that he has no human subject, so uses himself as that subject. With that latter issue, he discovers that his use of the serum changes his being to a female, who he is passing off as his widowed sister, Mrs. Hyde. That transformation initially helps his cause as Mrs. Hyde takes over the murders. But as the Spencers, who live above him, become more ensconced in his life - Howard Spencer who is attracted to Mrs. Hyde, and innocent Susan Spencer having long pined for Dr. Jekyll - things become more complex as Dr. Jekyll and cold-blooded Mrs. Hyde battle for control of his being, Mrs. Hyde who could choose Susan as her next victim.—Huggo