Such is the clever conceit of Evan Morgan’s feature directorial debut, “The Kid Detective,” which picks up decades after Abe’s fledgling career was felled by a truly heinous crime. Oh, Abe (Adam Brody, sharing the role with young Jesse Noah Gruman in flashbacks) is still a detective — he’s even got the same office, just with the “kid” scratched off the old-school frosted glass door, he’s just “detective” now — but after his tween secretary went missing when they were still just youngsters and Abe couldn’t so much as come up with a suspect, the gloss was off his profession. And, in many ways, his entire life.

Morgan, who also wrote the film’s screenplay, nattily sends up all the usual tropes of the eponymous kid detective, imagining Abe as the kind of junior gumshoe who paid said tween secretary in soda pop and mostly used his skills to just totally ruin movie plots with twists he could sniff out a mile away. But what does that look like nearly twenty years later? Brody, who captured classic hangdog charm with his seminal turn in “The O.C.” and somehow never let it go (a good thing) is a canny choice for adult Abe, the kind of grownup who forgets to brush his teeth, has no idea what day it is, and still needs his parents to deliver his groceries. So, really, what does happen when a kid detective grows up? In Morgan’s hands, something curious, laced with pitch black comedy and a major dose of tragedy, a winking sense of genre, and a stellar performance from Brody. Morgan lets the audience in on his icy humor early, introducing the ill-fated kid secretary Gracie Gulliver (Kaitlyn Chalmers-Rizzato) as she practically skips down the streets of a cutesy small town to the classic tones of Nancy Sinatra’s “Sugar Town,” only to be kidnapped by an unseen villain and never seen again. Years later, Abe is still smarting from that unsolvable case, a heinous crime that he was wholly unsuited to solve, even though everyone thought he’d wrap it up in no time. These days, that cutesy small town has fallen into disrepair (no one even comes in for the potato festival anymore), Gracie’s beloved dad and the town’s mayor have committed suicide, and Abe is still saddled with small-scale cases (from finding a missing cat to sussing out a man’s sexual preference). It’s an amusing twist on the down-and-out detective story, and like so many stories that take that shape, Abe is about to be handed a major new case that could turn it all around. Unfortunately, it’s another case he’s deeply ill-equipped to solve.

Enter former child star Sophie Nélisse (best known for “The Book Thief”) as the Gracie-esque Caroline, who employs Abe to find out who killed her sweet boyfriend Patrick, recently offed by way of a truly gruesome stabbing. Morgan and Brody keep the film’s off-kilter humor and lo-fi appeal alive even in the face of some truly dark stuff, with Nélisse proving to be a charming foil for the constantly falling-apart Abe. As the duo dive deeper into the mystery of Patrick’s murder, seemingly meaningless clues and funny asides pan out into something bigger — just like they did in Abe’s youth! — and the once-celebrated detective seems on track to finally solving his first “adult” case. But that’s the rub, because for all of the film’s winking humor and clever constructs, “The Kid Detective” does ultimately have to grapple with some pretty adult issues. Abe long ago realized his pint-size smartie act wasn’t going to cut it and responded by just not growing up at all. What can possibly happen to an emotionally astray adult who is obsessed with crimes? Nothing good, and while the tonal shifts that “The Kid Detective” makes in its twisty final act don’t always feel natural and will certainly take some audience members by surprise, there is an honesty to them. As Abe pushes closer to the truth, the film moves into darker corners, as Morgan and Brody attempt (with only some success) to hold fast to the humor that has driven it this far. Abe, it seems, is an adult now, and it’s time for an adult story, with all the pain that might entail.

Grade: B-

Sony’s Stage 6 Films will release “The Kid Detective” in select theaters on Friday, October 16. As new movies open in theaters during the COVID-19 pandemic, IndieWire will continue to review them whenever possible. We encourage readers to follow the safety precautions provided by CDC and health authorities. Additionally, our coverage will provide alternative viewing options whenever they are available. Sign Up: Stay on top of the latest breaking film and TV news! Sign up for our Email Newsletters here.