Dr. Jekyll (Ralph Bates) is a scientist researching the cure of many diseases. He is a very reserved and shy man, and spends most of his time working on his laboratory. One day, his friend Professor Robertson (Gerald Sim) visits him and advises that he would probably die before the conclusion of his studies. Dr. Jekyll decides to research an elixir of life, based on feminine hormones, to permit extend his life and consequently end his work. He uses some female corpses to get the hormones. The effect of the elixir releases his `feminine repressed side' and he becomes an aggressive and beautiful woman, Ms. Hyde (Martine Beswick). When bodies finish in the city morgue, Dr. Jekyll starts killing women to proceed on his research. This is another charming movie of Hammer. Very theatrical, with a strong British accent and without explicit blood and killing, this film is a great entertainment. Fans will certainly enjoy it. My vote is seven.