What if the transformation experienced by Dr. Jekyll resulted in a female form instead of a monstrous one? Around 1880, a series of murders targeting prostitutes began occurring in Whitechapel, east London. A professor (Gerald Sim) becomes suspicious of a colleague (Ralph Bates), who is developing an unusual elixir intended to prolong life—an elixir that requires female hormones sourced from recently deceased individuals. Martine Beswick portrays Jekyll’s sister in the film. "Dr. Jekyll and Sister Hyde” (1971) marks the third Hammer production drawing inspiration from Robert Louis Stevenson's well-known 1886 story. Previous adaptations include "The Ugly Duckling" (1959), a horror comedy, and “The Two Faces of Dr. Jekyll" (1960). While “Two Faces” is generally considered the strongest installment, “Sister Hyde” offers some intriguing elements and noteworthy moments. The screenplay incorporates details from two historical accounts of serial killings: the Jack the Ripper murders, which transpired between 1888 and 1891, and the Burke and Hare murders that occurred in Edinburgh in 1828. Given that Stevenson’s 1881 story “The Body Snatcher” was itself based on the Burke and Hare case, screenwriter Brian Clemens felt this would be a suitable addition to the narrative. I appreciate how Jekyll rationalizes his actions, claiming they are for the supposed betterment of humankind. A significant departure from the original storyline is facilitated by the physical resemblance between Bates and Beswick. As is typical of Hammer films, there are several attractive actresses present, both in leading roles and as supporting characters. Besides Martine, Susan Brodrick appears as the charming Susan, along with a few others. The film’s running time is 1 hour, 33 minutes, and it was filmed at Elstree Studios, Borehamwood, Hertfordshire, located just northwest of London. GRADE: B-

Source on TMDB