Gloria (Lola Dueñas) is a single mum in dire need of some male attention. Apprehensively, she agrees to go on a blind date found on a dating site. The man her girlfriend urges her to go for, Michel (Laurent Lucas), sweeps her off her feet over lunch, and without reservation the two end up in bed together. Well, actually outside her front door, but you get the idea. Gloria falls madly in love with this mysterious shoe salesman, and doesn’t hesitate to lend him money after just one night together. Alas, he doesn’t return her phone calls, and it looks like Gloria, so hungry for companionship, has been stood up. But she won’t take no for an answer, and she seeks Michel out. Turns out the smooth talker is a predator, seducing women to collect money off of them and then drop them like flies. But Gloria does not mind, and offers to become his partner in crime: he’ll seduce the women, while she takes care of him. A surprised Michel agrees, and so their disturbing relationship starts, but he is not prepared for the raging jealousy that can consume Gloria. Nor the fact that she soon turns out to be an unhinged psychopath. Who would have known, this mousy shy woman?

And thus Alléluia develops into a romantic comedy so dark that people should bring a flashlight to their screening. Gloria does not want her Michel to actually sleep with other women, and when it does happen there are bloody consequences. After she offs their first victim, Marguerite, we are treated to what is certain to be one of the most bonkers scenes on the Croissette this year. I won’t let the cat out of the bag completely, but Dueñas has a nice singing voice and knows how to handle a saw.

More victims fall, as Michel simply can’t subdue the urge to seduce his victims, nor can Gloria subdue her fatal rages. But once we get to Solange (Helena Noguerra), a rich mother with a young daughter that enamours Michel, the Bonnie and Clyde from hell seem to be growing apart. Michel shows true affection for both mother and child, and does everything he can to keep Gloria in check.

I’m wary of using profanity in reviews, but in this case it is unavoidable: this film by French director Fabrice du Welz is completely fucked up. As a co-writer of the screenplay, du Welz has created a romantic duo that puts Natural Born Killers to shame. Lola Dueñas and Laurent Lucas delve into their disturbing characters with glee, and especially Dueñas is frighteningly good in her transformation from attention-deprived mom to bloodthirsty femme fatale. Meanwhile, Lucas switches from utter fear for Gloria to his most maniacal grin for his next victim with ease. The two actors push each other to great heights in visceral, no-holds-barred performances.

Meanwhile, even if this is all darker than dark, du Welz manages to give his audience true laugh-out-loud moments. The director also doesn’t shy away from horror-level gore, and the blood flows freely, often shown in dark, grainy images that can turn into fever dreams at the drop of a hat. Gloria’s mood swings are reflected in the camerawork, and effective use of extreme close-ups allows Dueñas to show that there is a human being inside her character. A soundtrack that enhances the insanity adds further to the atmosphere.

The film offers no real redemption, so audiences will be left in doubt on how to feel about it, but those willing to let their evil side take over will be deeply satisfied with this concoction of blood, sex and pitch black comedy.