It’s not every day the cinematic world delivers a humorous slasher film in which a pregnant mother is doing all the slashing, all because her baby tells her to do so. Seven months pregnant herself during an eleven-day shoot, British actress Alice Lowe goes all the way in establishing herself as a triple threat for her directorial debut. Lowe previously co-wrote and co-starred in Ben Wheatley’s genre-mixer Sightseers (2013), and it was such a wickedly offbeat comedy of deathly errors that one can see how naturally Lowe’s tonal deftness came to fruition for Prevenge (2017).

Lowe plays Ruth, a pregnant mother who’s not in control anymore. With her partner no longer in the picture, it is just Ruth and her unborn daughter still cooking in her belly. When she’s not having check-ups with her midwife (a scene-stealing Jo Hartley), Ruth is out on her quest throughout London for revenge (for reasons that come to light later on) and the pushy demands of Ruth’s baby in a high-pitched, Shirley Henderson-ish voice make her do it each time. Whether it’s offing a creepy pet store owner (Dan Renton Skinner), a leering bar DJ (Tom Davis), a cutthroat business manager (Kate Dickie), or an exercise nut (Gemma Whelan) who doesn’t take well to charity door-knockers, Ruth also gives each victim a kiss on the forehead, post-murder, like a mother does to her baby before bedtime.

What might sound merely like a sick joke about pregnancy driving one to kill, Prevenge is actually a gruesomely funny doozy of a tar-black comedy. Since Ruth’s first few victims happen to be men, it also initially leads one to read it as a man-hating fantasy, but it’s anything but. Writer-director-actor Alice Lowe seems to be getting at a nugget of truth most hormonal mothers can probably identify with (this male writer can only assume). Ruth is deeply bonded with the little girl growing inside her belly and will satisfy her no matter what, even if that means corrupting her mind in the process to see what is morally right and wrong. As we come to learn, Ruth’s lover died in an accident made by the tough choice of his rock-climbing team, but Lowe reveals it in a way that’s gradual and not so blunt. Even if the consequences of Ruth’s actions never seem to manifest, what is next for both Ruth and her baby is pretty clear by the end.

Mining drolly biting humor in a surreal, warped situation, Prevenge is the sort of film where a woman can viciously kill a man in his flat and then warmly offer the dead man’s mother/roommate hot chocolate before tucking her into bed. Lowe gets away with this delicate tonal balance more than once. After finishing up one of her kills, Ruth lays in bed and moans to herself and her baby, “Kids are so spoiled these days. ‘Mummy, I want a Playstation. Mummy, I want you to kill that man.’” It’s one of several lines that works like gangbusters due to Lowe’s crack deadpan comic timing and the mere exasperation that Ruth is feeling. In front of the camera as Ruth, Lowe is excellent — relaying her cracking emotional state in alternately sad, pathetic, and disturbing ways — but also adorably hilarious as a woman simultaneously bearing life and taking life from those her baby thinks deserve it.

With the emergence of female-driven horror films this year, like XX (2017) and Raw (2017), Lowe’s Prevenge cements itself as a vehicle for a fresh voice, effortlessly twisting expectations and juggling tones. For a low-budget effort, shot in less than two weeks, the film is a solid, resourceful production, with a moody but not overbearing synth score composed by Pablo Clements, James Griffith and Toydrum. While the filmmaker’s sharp sense of gallows humor ever so slightly lightens the violent shocks of sliced throats, there is actually a surprisingly moving poignancy that hits and sneaks up on the viewer, too. Mothers-to-be won’t find any stories that draw blood quite like this from reading “What to Expect When You’re Expecting.”

Prevenge is available in selected theaters across the US and on VOD from 24th March 2017.