What a world Judd Apatow has given us. The modern comedy landscape is a place where both sincerity and depravity reign with equal power, where both coexist and intermingle in a sometimes awkward embrace. Apatow has cultivated this relationship so fully that even the comedies he doesn't have anything to do with come prepackaged with his sick/sincere stamp. Which is to say that the new comedy 21 Jump Street, starring Apatow acolyte Jonah Hill and curious shapeshifter Channing Tatum, is both a charming story of second-hand redemption and an exhausting two-hour-long penis joke. This is the Apatow style and we'd better learn to love it.

Let's deal with the good half of that equation first. Jump Street, based on a 1980s TV show best known for launching Johnny Depp's career about undercover detectives posing as high school students, presents us with lovable loser Schmidt (Hill) and oafish prom king Jenko (Tatum). They are seven years out of high school and find themselves strangely bonded together as the lowest peons on the Metro Police Squad totem pole. Schmidt feeds off of Jenko's physical prowess and cocky confidence, while Jenko relies on Schmidt's intellect and rationality. It's not a terribly creative pairing, but it's not really supposed to be. These are easy archetypes that are drawn rather broadly by screenwriter Michael Bacall so that Hill and Tatum can fill them in as they see fit. And they're quite good at it! Hill gives his frustrated nerd an interesting chord of sneakiness while Tatum is admirably adept at parodying himself; his strut is almost a limp, his mumbled b-boy cadence verges on speech impediment. Neither actor is doing a ton of work here, but whatever shading they do choose to add lands cleanly and smartly. Throw less capable actors into this noisy pile of jokes and the whole film is sunk.

As cops, Jenko and Schmidt are total screw-ups, so bad at their jobs that they are sent to the deep recesses of the force, into an undercover unit that sends young-ish looking officers into high schools to bust drug rings and other nefarious teen misadventures. Our heroes are chosen to go sniff out the source of a popular new drug that has just killed a student who, hours before his death, filmed a viral video chronicling the various stages of the drug's high. (That the kid freakin' died is an oddly grim detail, but whatever. More people will be dead by the end of this film.) So Jenko and Schmidt head off back to high school, Jenko assuming he'll ease in with the popular kids while nerdy Schmidt investigates the science geeks who might know who's been stealing the lab chemicals needed to make the drug. But, in the movie's most winning and clever touch, both dudes are forgetting that they haven't been in high school for almost a decade and that the rules have changed. They quickly learn that, like, being a nerd is cool now, that gay slurs are total no-nos, and that not trying — which was Jenko's number one strategy for social success in his high school years — is a near unforgivable sin. How the tables have turned! This means that Schmidt is more apt with the cool crowd — whose ringleader, played by Dave Franco, is our prime suspect — and Jenko is relegated to hanging with the geeks. This of course gives Schmidt the opportunity to live the social narrative he always wanted to but never could in his own high school years, while Jenko undergoes a period of enlightenment, finding chemistry fun and learning to be more confident in his mental abilities. Aw.

So that's the nice part of the story, one handled with a surprisingly kind and delicate hand. Even when our leads are hideously mortified, it's done so with an odd sweetness. This aspect of Bacall's script truly gets, with only a few exceptions, the tricky and subtle dynamics of high school socializing. Here the humor is in what we find familiar and believable. Particularly, Franco, younger brother of James, is so good at playing the laid-back but deceptively mean popular kid that it's hard to imagine he's a very nice person in real life. 21 Jump Street excels when it's going for the real, specific humor that Hill, with his piquant flusteredness, is so good at, and that Tatum, always smarter than he looks, shows a clear knack for. In this aspect the movie is way cleverer than it has any right to be.

But then the rest of the time it's dick this, balls that, etc. etc. That kind of stuff can certainly be funny, but only in moderation. And there are times when this movie sings with whacked-out filth and over-the-top inanity. But, as Ice Cube's blue-streaking commanding officer quickly proves, bad words and other silliness gets a bit tiring and repetitive after a time; it loses all its potency and saps the movie of energy faster than the good parts can create it. So, that's too bad. The bloody action climax (featuring a respectably not-tiny cameo by original Jump Streeter Depp) is fun, I suppose — directors Phil Lord and Chris Miller (Cloudy with a Chance of Meatballs) make the pictures zoom and flash appropriately — but the whole setup is a bit worn-out by that point, so I was mostly just eager for the thing to wrap up. And wrap up it does, loudly and with one last punishing penis joke, as if to remind us what kind of movie this is really supposed to be. Oh how I wish the movie had remained in the high school hallways, stayed a defiantly male Never Been Kissed, instead of thinking What Would Judd Do and going for the crotch shot. That would have been something special, but as is, this ultimately juvenile class project gets merely a C+.