***A SIMPLE FAVOR—2 STARS***

In February of last year, Collider entertainment columnist Haleigh Fouch (assisted by Brian Formo) put together a tidy and telling analysis of the famed indulgences and trash known as the erotic thriller. Complete with a list of recommended exemplars to place ahead of Fifty Shades of Grey, Fouch’s piece defined the dying breed discipline as the “back alley bastard child of noir, pulp, and Hitchcockian paranoia” and championed that the best among them “entangle their lurid affairs into compelling mysteries and dramatic tales.” When done right, even the most outlandish tales can be sensational film experiences.

Putting the women in charge instead of the men in this modern landscape, Paul Feig’s A Simple Favor had the dreamy cast and pulpy source material locked in to invigorate the subgenre. Instead, the Bridesmaids and Ghostbusters comedy specialist and Nerve screenwriter Jessica Sharzar couldn’t help themselves. Satire is their aphrodisiac and they brought it to the wrong bedroom. Kinky and quirky can be fun, but that mix is tenuous at best. Watching A Simple Favor devolve from intrigue into incompetence is like pouring chocolate sauce over a sizzling steak.

The kitschy over the kinky begins with the living embodiment of pluck, Anna Kendrick, as Stephanie Smothers. She is a widowed and saintly single mom of insane naivety who has unlocked every possible achievement Pinterest has to offer (if had them to offer). Outside of her equally well-mannered son Miles (Joshua Satine), her greatest joy comes in hosting her own vlog of self-help and DIY parenting tips ranging from cooking to crafts. Her impossibly spritely perfection makes her the butt of jokes among her parenting peers.

That husk of homeliness changes for Stephanie with the vintage Parisian pop-backed arrival of a hot flash named Emily Nelson, played by a glamourous Blake Lively. Cussing up a storm, slurping martinis effortlessly, and dressed to the hilt in top threads, Emily is a high-powered PR executive for fashion icon Dennis Nylon (Homeland Emmy nominee Rupert Friend). The mom is the diametric incarnate of everything Stephanie is not as a woman and parent. Emily’s formerly successful writer husband Sean (Crazy Rich Asians’ tall drink of water Henry Golding) is her trophy rather than the other way around. Her elegance is intimidating to all who cross her path.

Starstruck in many ways, Stephanie’s clings to Emily’s inspiring vivacity while the vamp exploits the submissive’s overeager helpfulness. The guessing game of whether or not there is validity and honesty in this newfound friendship begins with this film’s titular implied request. Emily asks Stephanie to do her a solid in watching her troubled son Nicky (Ian Ho) overnight. When one night turns into several and Emily doesn’t return calls or texts, Sean and Stephanie fear the worst. This opens a spooky missing persons case and whodunit which Stephanie plays out for all to see on her silly vlog, rousing even more rumors and gossip.

The conversational and corporeal chemistry between Kendrick and Lively is rollicking and zesty at the same time. Anna Kendrick might as well be this generation’s Diane Keaton as a light comedienne. Her staccato dialogue delivery of nerdy nervousness polished to a shine with her perfect smile has the same power as Keaton’s signature dithering. Even dialed to 12 here, that cadence of character is utterly believable as the confined and repressed control freak. Similar compliments are earned by Blake Lively using her beauty to become an Americanized sex kitten equal to Brigitte Bardot, the original inspiration for the term. The two play their types very well with little glints at possible hidden nuances.

What fails this fascinating combination are the extra ingredients that fizzle and stifle the matters at hand rather than coalesce and combust their potential heat. Infusions of humor can be effective at disarming tension with sinister glee, but it can also, quite frankly, just be weird, especially when applied to dramatized themes of true crime or eroticism. A Simple Favor is problematically uneven because the lampooning humor dulls its thriller edge and source.

There is, unfortunately, not a great deal of surprise in A Simple Favor when those types stay their types without any convincing twists, especially when Hendrick’s Stephanie shifts from a mark to being a Velma-like gumshoe and snoop (who coincidentally probes a former Velma herself in Linda Cardellini). What lurid turns arrive in A Simple Favor are laughable, which is likely the intentional point of the farce of it all, but it is also harebrained proof that it did not have the moxie to pull of the sultry side to stand out and really twist the proverbial knife of mystery. Even with attempting a clever sense of self-awareness, if your script requires your characters to announce and namedrop their Diabolique and Gaslight schemes and references, the heady smarts are being devalued.

LESSON #1: SECRETS ARE LIKE MARGARINE — This lesson is the beginning of a dynamite nugget delivered Lively’s Emily. Its connected kicker is secrets are “easy to spread” and “bad for the heart.” File that perfectly in the truer-words-have-never-been-spoken folder.

LESSON #2: STOP SAYING YOU’RE SORRY — Quickly-tossed “I’m sorry” statements are meaningless air-fillers compared to a properly formed answer or reassessing the situation if an apology is even necessary. As Emily scolds, “apologizing is a f — ked up female habit,” and, for the second time, she’s not wrong.

LESSON #3: SIMPLE FAVORS ARE RARELY EVER SIMPLE — Be aware that people who label their requests as such are often masking their difficulty or required commitment level. Try before you buy. Establish trust and get the details before agreeing blindly. Along the same lines, watch your use of the word “anything” in this context. That word can be taken as a blank check resulting in your disadvantage.