Though not readily apparent by its title, The Four-Sided Triangle belongs in the realm of science fiction/fantasy. Barbara Payton stars as Lena, a British girl raised in America who returns to her hometown on a sentimental journey. Here she is reunited with her childhood friend Bill ( Stephen Murray ), now a scientist. With the help of his pal Robin ( John Van Eyssen ), Bill has developed a duplicating machine (today it'd be called a cloning device). When Robin and Lena fall in love, the heartbroken Bill decides to create a duplicate Lena, whom he names Helen. Unfortunately, since Helen is an exact copy of Lena, the clone falls in love with Robin as well! A climactic fire claims the life of one of the two Lenas—but which one? Director Terence Fisher co-adapted the screenplay from a novel by William F. Temple . — Hal Erickson