At its core, the bond between these two buddies — as Finn matured from adolescence to young adulthood — became credible enough to generate real emotion and intelligence around even the most outrageous of circumstances, and it bled into the rest of the show as the ensemble grew. Over the past year, the fruits of that silly-poignant balance has bled into a series of fascinating HBO Max specials that build out the “Adventure Time” universe, starting with the cosmic prequel odyssey of the guys’ lovable sidekick in “BMO” and continuing with the delightful Marceline-PB romance of “Obsidian.” Now comes “Together Again,” the penultimate entry in the quartet of “Distant Lands” specials, which returns us to Finn and Jake for what appears to be their final chapter. For real this time.

And that’s what’s strange about it. Revealing too many details about the premise of “Together Again” (including its actual title!) would spoil the specifics, and in fact, the network gave journalists a laundry list of plot points that had to be kept under wraps in order to preview the episode in advance. Needless to say, this is the “Lost” finale of the “Adventure Time” EU, careening into an incredulous set of circumstances in a quest to show how the Finn and Jake relationship transcends time and space. If it had been the official finale to the show, it might been a source of frustration. As it stands, this is endearing, nice-to-have fan service that doesn’t reach the same level of ingenuity typically found on the show. Yet there’s plenty to enjoy about the 40-odd minutes of adventuring herein. It’s often a lot of fun to see these characters evolve even as they retain the same youthful naïveté that made them so appealing in the first place, and here we get an elderly Finn on a worldly odyssey to track down Jake from a strange realm, only to realize that circumstances have changed well beyond anything they can control. Showrunner Adam Muto (who took up the reigns from creator Pendleton Ward) nails the “Adventure Time” aesthetic each time out, and the progression through different tones here is no exception. It begins in a dark underworld and careens through trippy, colorful other dimensions loaded with delightful psychedelic imagery and the usual kind of slacker understatement that makes the show’s writing such a joy. (“I was hangin’ out in nirvana beyond all desire when I picked up your vibe” is an instant classic.)

Fans of the show will certainly enjoy the range of cameos from familiar faces, from Tree Trunks (whose appearance marks the final performance of the late Polly Lou Livingston) to Lumpy Space Princess, a smarmy fox and some antiheroes are alternatively an amusing source of frustration and dread. Jake’s parents (who are also Finn’s adopted parents) resurface for an enjoyable action showdown that builds up to a final reveal, with its heroes beaten and bruised but no less chipper than ever before. There’s a touching moment that bears an uncanny resemblance to Pixar’s “Soul” as Finn and Jake contemplate the next phase of their existence and by the time we get there, the episode has made it clear why they turned into two of the most iconic animated characters of all time: “Adventure Time” didn’t reinvent the formula for animated children’s shows; it used their mold to explore more complex aspects of a difficult, contradictory universe that can shift from light to dark in a single frame. The episode not exactly called “Together Again” finally retitles itself as such at the end, and in doing so, it sidesteps the emotional hardship of losing someone forever. No, Finn and Jake aren’t really together again. Nothing lasts forever. But it’s nice to see them anyway.

Grade: B-

“Adventure Time: Distant Lands – Together Again” is now streaming on HBO Max. Sign Up: Stay on top of the latest breaking film and TV news! Sign up for our Email Newsletters here.