The question of how director Paul Feig was going to follow five consecutive feature comedies - four of them assembled through shaggy hang-out improvisation, often centered on Melissa McCarthy's particular comic rhythms - with an adaptation of a nasty-minded beach-read thriller was so damn confusing that it even formed part of the ad campaign for A Simple Favor. For that is the thriller under consideration, adapted by Jessica Sharzer from a 2017 novel by Darcey Bell. And the answer to the question is simple enough: by making it into a comedy.

Indeed, A Simple Favor: The Movie comes damn close to being a parody of the "murder mystery among the wine moms" genre, typified cinematically by 2014's Gone Girl and 2016's immodestly schlocky The Girl on the Train. It is, at the very least, a pretty no-holds-barred piss-take of such stories, and it gets there in the Feig-iest way possible: by putting two talented actors in two key roles and letting their performances guide the tone of the thing. In particular, the film bets pretty much everything on Anna Kendrick as Stephanie Smothers, a widow living in a posh Connecticut suburb of New York, counting out the days until her husband's life insurance money runs out, and meanwhile attempting to make a go of it with her vlog where she offers helpful life hacks to busy moms. The second thing we encounter in the film is the latest of these vlogs, which Stephanie starts with a robust "Hi moms!" and continues to speak with a very driven level of good cheer, one that remains aggressively switched-on even when she's speak with downcast eyes and sober tones of the recent tragedy in her life.

(The first thing we encounter in the film is title sequence whose playful manipulations of text and swatches of color communicate, even more clearly than the accompanying brassy notes of the 1967 Jean Paul Keller song "Ca s'est arrangé", that we're in for a movie that adores the slinky cool of 1960s European pop culture and style).

Then we scoot back a few weeks to see the origins and evolution of that tragedy. Stephanie's son Miles (Joshua Satine) is attending a high-end elementary school, and his best friend is Nicky (Ian Ho), the son of a couple parents that nobody ever much sees, much to the gossipy pleasure of fellow parents Stacy (Kelly McCormack), Sona (Aparna Nancherla), and Darren (Andrew Rannells), who drift through the film like a catty Greek chorus. Only one particular day, Stephanie happens to cross paths with the much-mythologised Emily Nelson (Blake Lively), Nicky's mother, and the head of PR for a fashion house in the city, and through their sons' intervention, the women end up having a martini date at Emily's gorgeous, chilly mini-mansion. This gives Stephanie plenty of opportunity to witness all kinds of appealingly sordid details of Emily's life: her very high-funcitoning alcoholism, her sense of humor based almost entirely in tossed-off cruelty, her astonishing marriage to Sean Townsend (Henry Golding), which consists of the two spitting vindictive insults while hungrily pawing each other right in front of company.

One day, Emily asks a simple favor, requesting that Stephanie pick Nicky up at school; Stephanie, who has already halfway turned into an unpaid nanny happily does so. And then Emily goes missing. Stephanie and Sean get heavily involved in the investigation, and when Emily's car and Emily's body show up in a lake in Michigan, they get heavily involved in each other's pants. But Stephanie remains unconvinced that things are what they seem, and starts playing amateur sleuth.

There's any number of places this can go, and I gather from what little I've heard about the book is that it plays this pretty straight: a mommy vlog Nancy Drew story, loaded up with more and more scandalous twists as it goes along, because that's what stories like this do. I've also gathered that the book is pretty shite, so it probably makes no small amount of sense that the filmmakers have elected to travesty it in such a high-spirited way. The film doesn't really do anything specific to be funny, though it is even so maybe the funniest thing Feig has ever directed (and a pretty clear sign of the value of working with a screenplay rather than assembling a movie out of mountains of improvised footage); mostly, it's just dialing up everything about its setting and characters to a terrifically overstated degree. Expressing itself mostly through Stephanie's POV, the film accordingly adopts her worldview: everything in the design is full of bright, sunny colors, given maximum intensity through John Schwartzman's best cinematography in a decade or more. Many, many of the gags consist of very little other than having the bleak stuff of noir delivered in an inflexibly chirpy tone of voice by Kendrick, giving one of the most focused performances of her career; many of the others consist of nothing but a perfectly-timed beat elapsing before Kendrick overwhelms the thriller tone with the same can-do enthusiasm of a real top-shelf mommy vlogger.

Not that the film is all seriousness outside of Kendrick. A Simple Favor's obvious, but not therefore ineffective, tactic is to treat everything with a very breezy, tossed-off sensibility; it's a pretty great attempt to split the difference between outright camp and chic Eurocool of the sort promised by the credits and much of the soundtrack ('60s French pop is used motivistically for Emily), and if it largely shifts towards camp as it goes on, that's in no small part because of how much Stephanie starts to take over the film after Emily vanishes.

The film isn't ultimately much a satire of a narrative genre, that's just the tool it uses; mostly, it's a satire of the mindset fueling that genre. Stephanie, Emily, and Sean are a perfect trio of everything broken and bad about the overpriced suburban lifestyle they're trapped in (it is made explicitly clear that both families are living above their means), never in the expected ways. Stephanie is initially a parody of the kind of overachieving Super Mom that everybody else hates, and the initial joke is obviously that her achievements have left her so desperately lonely for the friendship of another adult that she'll latch onto the mocking, contemptuous, abusive Emily just out of the need to have anybody to talk to. And then the joke turns on its head as we learn that, in fact, Stephanie's actually a moral monster. Similar arcs work their way out for Emily and Sean. The film doesn't judge its characters for being bad; it seems to be the implication that this just kind of goes with the territory of living in an upscale suburb. Rather, it exults in their badness; every one of the three main characters is at least once made out to seem like the sympathetic innocent being horribly wronged by the other two, and this invariably happens at a moment when the "sympathetic" character is being actively terrible. That's the kind of heightened black comedy we're working with: A Simple Favor is a movie that concedes the rottenness of this society early on and therefore allows sociopathy as both the only reasonable reaction and perhaps even the righteous thing to do.

That pitch-black approach to life, plus the all-encompassing campiness with which Kendrick's indefatigable vlogger plunges through life, leaving the movie desperate to re-shape itself around her ("Hi moms!" becomes a constant rallying cry, and it never ever gets less silly), plus Lively's magnificent array of sleekly androgynous costumes, plus the song-related gags, plus the overall cheeriness of such a sick-hearted movie, is enough to get A Simple Favor working long before it starts really showing off. And I can't talk about that without spoiling things. Let's just say that the film has a lot of twists, all of them very filthy and nasty, and they are played up as both impossibly ludicrous and overwhelmingly joyful - for what, after all, is more fun to watch than the completely ludicrous? Here again we're somewhat at the mercy of the actors, with Lively especially finding exactly the right amount of annoyance and self-amusement to suggest that the character is aware of how dumb this is, wishes it weren't, but shall have fun with it anyway (the big key here is the perfect way she repeatedly delivers a phrase based on the word "fuck" - even to name the phrase would be a spoiler - as a jolly, vulgar term of endearment like one might use on a cherished pet). Whether it works is, I suppose, in the eye of the beholder; but I pray that most of us can behold something as outrageous, as high-energy, as lovely, and as fun as A Simple Favor and find something to attach to.