One of many slightly-inebriated key moments in the new documentary Mistaken For Strangers—nominally about The National, but really about sibling rivalry and the struggles of being a lifelong underachiever—occurs when director/roadie/little brother Tom Berninger listens to Rob Halford's Christmas album alone on the tour bus. Throughout the film, metal fan Tom has complained about the band being too "coffeehouse;" instead of Jack-and-Coke fueled bacchanalias—Tom was stuck with lots of footage of people on laptops.

The moment encapsulates Tom's aimless sadness; it also points to his often hilarious, admiringly-pious belief in keeping things real. And it's that very quality—his ability to eventually look himself in the mirror and admit what a fuck-up he has been—that ultimately led to him completing his first feature-length documentary. And making it a damn good one at that.

The Tribeca Film Festival opened last night with the world premiere of that movie: it's part-backstage rock doc, a glimpse into the everyday happenings of one of the most famous indie rock bands on their biggest tour ever. But even more so, it's the story of how Tom confronts living in the shadow of his much more successful "golden boy" older brother, lead singer Matt Berninger.

There's only a handful of concert footage included in the film (make sure you stay till the end though, or else you'll miss goosebump-inducing video of the band performing "Terrible Love" at BAM in 2010 with Tom doing his darndest to follow Matt as he gallops across the venue), and halfway through the film, Tom is fired from his job as a roadie. The last third of the film just concerns whether Tom can overcome his own low expectations and actually assemble a final product. The support of Matt and his wife Carin Besser, who let Tom move into their daughter's playroom in order to complete the film, can't be underestimated.

It's not much of a spoiler to say that he is able to pull it together—having your first major film introduced by Robert DeNiro and Richard Belzer is a credit to that. The film may use The National and the tour as more of a backdrop/jumping off point for an exploration of siblings, but Tom is able to key into the same intimate, bruised tone as their music does. If you're a National fan, you'll definitely want to see this; but even if you're not, this unique documentary speaks to the dynamics of family relationships with candor and humor that never dips into the maudlin or sentimental.

The night transitioned from the premiere to the Highline Ballroom for an afterparty with The National performing a tight 10-song set. Four new songs from their upcoming album Trouble Will Find Me were played, including a propulsive, blistering version of new single "Don't Swallow The Cap" (or "Don't Swallow The Crap," as Matt noted someone on their website's forum called it), the multi-sectioned rocker (one of the more agressive songs they've produced in recent years) "Sea Of Love," and the beautiful, lilting "I Should Live In Salt," which Matt revealed was written about Tom ("Don't make me read your mind, you should know me better than that").

The show started with a surprise version of "O Holy Night," done in the style of Hatford, one of Matt's many tributes to his brother. And the evening ended with Matt again heading into the audience to perform "Terrible Love"—only this time, he went looking for Tom, who hugged his legs as Matt screamed lyrics about walking with spiders.

1. Oh, Holy Night
2. Bloodbuzz Ohio
3. Demons
4. Don't Swallow the Cap
5. Mr. November
6. Sea of Love
7. I Should Live In Salt
8. Fake Empire
9. Terrible Love