Charles Manson spent the 1960s assembling a following at a California ranch before turning them into killers. On August 9, 1969, members of his group murdered five people at the Los Angeles home of actress Sharon Tate, then eight months pregnant; the next night they killed two more. The film traces how Manson, a failed musician recently out of prison, convinced his followers he was a messianic figure decoding a coming race war from the Beatles' White Album, and how he used that belief to order the killings. It follows his ties to the music industry, including his relationship with Beach Boys drummer Dennis Wilson, and the industry's unease once his crimes became public. Archival footage and interviews place the murders as the moment the counterculture's ideals of communal living and free love curdled into something people no longer trusted. Manson died in prison in 2017, but the film's real interest is in the year before the murders, and how an ordinary drifter built a following willing to kill on his word.