A Serial Killer's Guide to Life (2019)

Lou Farnt is a meek young Englishwoman with poor self-esteem, who is emotionally browbeaten by her harsh and demanding mother, with whom she lives. Wanting something better, Lou follows the teachings of various self-help gurus, but especially that of Chuck Knoah. At a different self-hep guru's lecture, Lou sees a middle-aged women who strikes her attention.

But when she looks again, the woman is gone. She later meets the woman, who introduces herself as Val Stone, a self-help teacher who believes she would be perfect for Lou. A day later, at Val's invitation, Lou visits her at a caravan park. There, Lou describes a road trip of discovery she is taking the next day, and insinuates that Lou should join her. Despite being flattered by the attention, Lou initially can't bring herself to leave home for an extended time for the first time. But her mother's emotional abusiveness changes her mind. The next day, Lou leaves with Val in a car, for the purpose of visiting various types of self-help gurus for research. A radio briefly mentions that a woman has been found murdered at a caravan park. With Val periodically leaving voice mails to let her mom know she is alright, they make their first stop at a wilderness retreat led by Ben. After engaging in some activities such as tree hugging, pitching camping tests and listening to one of the three other attendees provide evening entertainment by singing a song in Welsh, they all turn in. The next morning, Val hurries up Lou to leave. After they do so, we see the dead bodies of Ben and the attendees, their heads bashed in. The next stop is a "sonic vibration" retreat, where Lou and Val are the only two attendees of the husband-and-wife couple who run it at their large house. The following morning, Val knifes the wife to death, with Lou witnessing the aftermath. The husband stumbles onto the scene and tries to escape into the yard, but Val, wielding a knife, catches him. The two struggle, and Val is being overpowered when Lou kills the husband. Lou and Val leave their car behind and take the couple's minivan. As radio news begins reporting about the murders, Lou has Val pull over in order to throw up in a field. Val goes to her, and Lou angrily wrestles with her and soon has Val in a choke hold. Val urges Lou to kill her. But Lou cannot, and the two lay exhausted in the field. Val calls Lou the best student she's ever had. They visit a laugh-therapy workshop and murder the members. Then during a visit to a birth-memory guru, Lou, while Val waits in the hall, begins to hallucinate. She has a memory of herself killing her mother before leaving on this trip, with the image inter-cutting with that of Val murdering her mother. The two finally arrive at Chuck Knoah's estate. They find him a pathetic wreck, going through a terrible divorce and about to be dropped by his publisher for having no new book ideas. Ironically, once Knoah realizes these are the two serial killers on the news, he says his publisher would just love their memoirs, and is on a phone call arranging a meeting when Val shoots him in the head. Lou knifes Val, who earlier had called the police in an attempt to frame Lou and escape. A gun-wielding Val chases Lou to the edge of a cliff, and there they have a final meeting-of-the-minds as police sirens and a helicopter close in. Val shoots herself and the two fall on the grass. But moments later, when police arrive, Val seems to have vanished. The film ends with a repeat of the opening scene of Lou, walking outdoors, wearing earbuds and listening to a recorded Knoah lecture. (copied from Wikipedia)