Joe Swanberg is 33. I don't know whether to be amazed by how high or low that number is. 

On one hand, that's ridiculously young for a filmmaker who broke out back in 2006 and 2007 with "LOL" and "Hannah Takes The Stairs" and has been absurdly prolific since then.

On the other hand, though, the filmmaker who made his name -- and, depending on your generosity, made a genre -- chronicling the dramatically limited foibles of recent college graduates has reached the "thirtysomething" phase of his career. The erratic and misdirected youths at the center of Swanberg's earlier films have become the pesky nubiles who show up to make Swanberg's new leads feel either old or optimistically mature.

It's a transition that has been in the works for a little while. Last year's Swanberg Sundance entry "Happy Christmas" featured the director and Melanie Lynskey as a grown-up, responsible couple whose house nearly burns down when they welcome flighty Jenny (Anna Kendrick) into their home. Jenny would have been the star of an early Swanberg film (probably played by Greta Gerwig), but in "Happy Christmas," whatever temporary rejuvenating powers she has for the central characters, she's the one constantly passing out and unable to find herself. They're the ones with the house, the love and the gigantic toddler.

Swanberg's latest feature, the Sundance out-of-competition premiere "Digging for Fire," cements either the director's maturation or else his commitment to wallowing in a different phase of life, again depending on your generosity. Simultaneously more plot-driven than most of Swanberg's early films -- There's a freaking gun found in the opening scene, instigating something that resembles a mystery -- and also more submerged in extended metaphor and symbolism, "Digging For Fire" is a messy movie, but it's also full of terrific little moments and you'd be hard-pressed to find a better ensemble cast at Sundance this year.

[More after the break...]

Tim (Jake Johnson) and Lee (Rosemarie DeWitt) are a decade into marriage and while they seem to be very much love, they're also subsumed by adult responsibilities, including their son Jude's ("Happy Christmas" scene-stealer Jude Swanberg)  pre-school future. Staying at a borrowed home up in the Hills, Tim has a looming weekend of tax paperwork, but that gets derailed when he stumbles upon a gun and a possibly human bone in the backyard. The LAPD isn't especially interested in Tim's discovery, but he becomes obsessed, with the help of an assortment of new and old friends (including Sam Rockwell, Mike Birbiglia, Steve Berg and a very exposed Chris Messina) and a couple mysterious women (Anna Kendrick, Brie Larson). Meanwhile, Lee tries to get a weekend on her own with her parents (Judith Light, Sam Elliott) and a couple friends (Melanie Lynskey, Ron Livinston).

Did I mention that this was just a bizarrely good cast? And that's before you get to drop-ins by the likes of Orlando Bloom, Jenny Slate, Timothy Simons and Jane Adams.

And for all of that, the "And" credit among the cast goes to Jude Swanberg, whose grasp of dialogue has improved since "Happy Christmas."

Both Joe Swanberg and wife Kris Swanberg have moves up at Park City this year and it's fun to see the couple dealing with similar themes in very different ways. 

In "Unexpected," Cobie Smulders' character faces an unplanned pregnancy while pondering her professional future and the loss of her identity as anything other than a mother. 

The idea of becoming so much a parent that you lose your identity as a couple and of becoming so much a couple that you lose your identity as an individual is very much at the center of "Digging For Fire" as both Tim and Lee spend a weekend apart trying to remember who they are and who they were. 

Leaving aside the relatively worthless "mumblecore" designation that probably hasn't been appropriate for his last handful of films (if it was ever informative), looseness has always been a key to both Swanberg's improvisation-heavy process, but also to his storytelling style. Here, Swanberg and co-writer Johnson seem to be getting a kick out of dramatic and almost theatrical devices. 

"Obviously I don't know the end of the mystery at the beginning of the mystery," Tim tells his wife after finding the gun and bone, as Swanberg and Johnson tease the audience with the notion that there's a puzzle to be solved here, even as we come to suspect very early on that the real mysteries are, spoiler warning, all internal. The gun and bone and hole in the backyard may be literal, but Swanberg and Johnson's interest in them is as metaphor. We all have a hole in our backyard, don't we? I don't. I have no backyard, but I think many married couples have their own backyard holes, just like many married couples have leather jackets that represent the fun people they used to be. Oh. Did I mention that Johnson and DeWitt's characters have unearth leather jackets over the weekend, leather jackets that represent the fun people they used to be?

"Digging For Fire" is that kind of movie and you have to be prepared for a certain amount of where-am-I-in-my-own-life noodling.

Fortunately, that's where the cast comes in, managing to hit the serious beats and also to contribute enough humor to keep the noodling from ever feeling like wallowing. [Got that? Noodling? OK, but not for everybody. Wallowing? Bad, but probably still for some people.] 

Johnson, who hasn't gone Sundancing since "Safety Not Guaranteed," welcomely doesn't play his "Digging" character as an extension of Nick Miller from "New Girl." It would have been so easy to take him as a man-child having a two-day  not-yet-midlife-crisis, but instead Tim is half-way between his ultra-responsible friends (the Birbiglia and Berg characters) and the wild chums from his past (Messina and Rockwell) and rather going in either direction, he goes down a hole of his own, which is how Johnson plays it. The arc avoids predictability and it's such a relief that Brie Larson isn't doing the Manic Pixie Dream Girl thing that I was almost willing to forgive that she's wholly underused. 

At the post-premiere Q&A, Swanberg and DeWitt talked about making sure that her character had an arc other than the wife who says, "Do your taxes..." and that actually comes through very nicely. DeWitt, who has done so many good things and yet always seems like a revelation when she's properly used (see "Your Sister's Sister" or "Rachel Getting Married"), never goes down that "disapproving spouse" path for a second, though she would indeed like for the taxes to get done. She has good moments with Judith Light and Sam Elliott and then a couple charming scenes with Orlando Bloom. There's a little smile that DeWitt uses to capture the character's interiority in several key moments, a smile that elides the necessity for monologues, but shows her amusement at, rather than "need for," this weekend of freedom.

DeWitt and Johnson are also good enough together in their first few scenes, cementing a stable relationship and giving us reason to hope that if the characters part ways, they'll meet again in the middle.

The thing that's most interesting about the size and star-studding of the ensemble is that while it's a pleasure to check off names from the big list, nobody's presence is distracting, but I also wouldn't tell you that anybody from the supporting cast is giving a "performance" that I have to single out. That's not an insult. Big actors pop up, they inhabit their few moments and they're gone. So Rockwell, Kendrick, Lynskey, Livingston, Birbiglia, Messina and the rest are all good because they occupy their spaces in this world naturally, but I don't think I'd tell fans of any of them that they're in the movie enough that you'd want to see it just for them. They're not stars of the movie, but they're part of it.

Joe Swanberg's movies always used to be described as acquired tastes, but then the wildly appealing "Drinking Buddies" came as close as he's come to doing something that people felt was "mainstream." "Digging For Fire" feels like another different thing entirely. It isn't just the plot conventions or the use of metaphor. Shooting on film, Swanberg's regular cinematographer Ben Richardson has given this what is certainly the most polished look yet for one of Swanberg's films, which combines with the LA setting for a reasonable freshness (and perhaps as a justification for the recognizability of the entire cast). It's all different and then it's tied together with a score from Dan Romer that I loved, but couldn't necessarily explain in context.

So "Digging With Fire" is an idiosyncratic little film. It doesn't exactly feel like you expect a Joe Swanberg film to feel, but it also doesn't feel like Swanberg has gone from DIY to studio stuff just because he has a dream cast. There are symbolic beats that are a little too on-the-nose and other parts that I wish had been explored more fully, but for all of its messiness, this was a hole I was happy to dig for 90 minutes.

Other Sundance 2015 Reviews:
"Prophet's Prey"
"The Wolfpack"
"Going Clear: Scientology and the Prison of Belief"
"Kurt Cobain: Montage of Heck"
"Slow West"
"The Amina Profile"
"The Hunting Ground"
"The End of the Tour"
"A Walk in the Woods"
"Finders Keepers"
"How To Change The World"
"What Happened, Miss Simone?"

A long-time member of the TCA Board and a longer-time blogger of "American Idol," Dan Fienberg writes about TV, except for when he writes about movies or sometimes writes about the Red Sox. But never music. He would sound stupid talking about music.