One might think that director Mary Harron (American Psycho, I Shot Andy Warhol) would fashion a biting tale about the Manson Family and their murder spree in the summer of 1969. Yet it is the lack of satire and style that reverberates through this humdrum film, yet another about the mythic “girls” who followed cult leader and failed musician Charles Manson (Matt Smith) over sanity’s edge. There’s promise in focusing on one of the more skeptical of Manson’s followers, Leslie Van Houten (Hannah Murray), and in using visits by a well-meaning graduate student (Merritt Wever) to the incarcerated Van Houten, Susan Atkins (Marianne Rendón), and Patricia Krenwinkel (Sosie Bacon) as a framing device. However, the movie’s depiction of these lost flower children, and what rendered them susceptible to Manson’s brainwashing, is frustratingly shapeless and shallow. Smith and Murray are miscast, looking and acting like rough drafts of their real-life counterparts, while the film itself is plodding and visually uninspired. A final note of wish fulfillment suggests what might have been if the talented team of Harron and screenwriter Guinevere Turner (American Psycho, The Notorious Bettie Page) had played more with fantasy, the state in which many idealists of the 1960s lived until the Manson murders, among other tragedies, punctured the spell.