Who's the more powerful teenager: Katniss Everdeen or Lorde?

Or to make it a musical question: In The Hunger Games: Mockingjay, Part 1, the box-office-topping third film adaptation from Suzanne Collins' novels, whose dulcet tones move the masses more? Is it the singing of the expert-archer celluloid heroine, played by Jennifer Lawrence, or the 18-year-old New Zealand pop star, whose real name is Ella Yelich-O'Connor?

If you answered the latter - as well you might, since the über-teen Kiwi is the force behind the movie's soundtrack, which also features Kanye West, Ariana Grande, Miguel, Major Lazer, Chemical Brothers, Sia, and more - you'd be wrong.

The most important music in Mockingjay comes from neither the Lorde lorded-over Original Motion Picture Soundtrack nor Academy Award winning film-scorer James Newton Howard. What most moves the story forward is the sorrowful folk song "The Hanging Tree," sung by the Kentucky-born Lawrence as Katniss and later taken up as a rallying cry by those opposed to Donald Sutherland's evil President Snow.

More on that in a minute. First, let's ask: What role is played by the music on the official The Hunger Games: Mockingjay, Part 1 - Original Motion Picture Soundtrack (Mercury/Republic nolead begins ***) nolead ends assembled or - to use the most pretentious and overused word in pop culture - "curated" by Lorde?

Absolutely none, other than to send theatergoers out the door. "Yellow Flicker Beat," the breathy, brooding dance track from Lorde and the album's first single, plays as the credits roll. And that's the only track from the album to be heard in the film.

Since the 2013 release of her Pure Heroine debut, Lorde has been on the ascent. She was handpicked by the surviving members of Nirvana to stand in for Kurt Cobain on "All Apologies" at the Rock and Roll Hall of Fame induction ceremony. She's been parodied not once but twice on South Park.

After opening the American Music Awards last Sunday with "Yellow Flicker Beat," Lorde spent the rest of the night hanging with BFF Taylor Swift. And her connection with her audience is downright Swiftian: At the Grammys this year, two of the three highest spikes in social-media activity during the telecast happened when Lorde was on stage.

All that explains why a blockbuster Hollywood franchise would turn over the music reins to a talented teen from Takapuna who was 15 and unknown when the movie series launched in 2012.

And the dusky-voiced singer with the leonine mane certainly has proven the faith of the Lionsgate studio to be well-placed. Mockingjay Soundtrack is no grab bag of the usual pop suspects. It mixes fresh tracks by rising not-yet-household names such as Atlanta hip-hop/R&B wunderkind Raury and Los Angeles songwriter Tinashe with unexpected pleasures such as the deliciously nasty tribal dub-reggae "Original Beast," from disco diva of yore Grace Jones. "Meltdown" pools the talents of rappers Stromae, Pusha T, and Q-Tip with L.A. sister act Haim and Lorde.

Maybe the biggest surprise is big-beat electronica act Chemical Brothers teaming with pop-R&B star Miguel on "This Is Not a Game," with lyrics that actually have something to do with the movie's populist-rebellion story line. However, "Flicker," the "Kanye West Rework" of "Yellow Flicker Beat," is a disappointing remix.

But if Lorde's work is so fabulous on Mockingjay, how come none of it is heard in the movie? We have it from an authority as trustworthy as Lawrence that "Katniss would be a huge Lorde fan," as she told the media during a press call in London. So why isn't the Girl on Fire from District 12 seen rocking out to "Yellow Flicker Beat" to get herself stoked to do battle with the Capitol?

For starters, there's anachronism. It would be weird, for instance, to put a Kanye West song in a movie set in the unspecified postapocalyptic future. Yeezus belongs to our dystopian present. But more to the point, the Soundtrack music doesn't actually need to be heard in the movie to serve its main function. It gives fans another way to keep J-Law as Katniss in their hearts between repeat multiplex visits. It's a Mockingjay marketing companion and brand-extender.

That's fitting for a movie in many ways about public relations. Partly because it's a setup for a slam-bang Part 2, there's not a whole lot of action in this Mockingjay. Instead, it's a futuristic flick about information wars that turn on a very 2014 concern: How do you cut through the noise and get your message heard?

The late Philip Seymour Hoffman's character, Plutarch Heavensbee, is a communication minister intent on broadcasting propaganda films that depict Katniss as the inspirational Mockingjay. He uses the films to call the masses to action, and thus fight back against Capitol "propos" hosted by Stanley Tucci's Caesar Flickerman. Katniss is taught to shout out rebel yells, but later it's thought better to send her into the field, where a more visceral rage can be caught on film.

That's where the music comes in. Inspired by the singing of mockingjays (a fictional hybrid species) flying above an unspoiled lake, Katniss breaks into an a cappella version of "The Hanging Tree," a song her father taught her when she was growing up in coal-mining country in District 12. Her camera crew catches the emotional moment.

"The Hanging Tree" isn't a folk song in the strict sense. Its lyrics are by book author Collins, and its haunting melody is by the Lumineers, the folk-pop band who contributed "Gale Song" to last year's The Hunger Games: Catching Fire - Original Motion Picture Soundtrack.

In Mockingjay, we first hear the song in Lawrence's unadorned take, then later with strings and a chorus of determined rebels. It becomes the theme song of a noble cause. In scenes that echo civil-rights protests of the 1960s, unarmed marchers use it as their own "We Shall Overcome." It's a motivational anthem to help them face the Capitol's "peacekeeper" soldiers - who look like a cross between Star Wars storm troopers and Bull Connor's hose-wielding police in 1963 Birmingham, Ala.

We hear "The Hanging Tree" one last time, following "Yellow Flicker Beat," as the Mockingjay credits roll to their somber end.

But those who want to take the evocative song home won't find it on the Soundtrack album. They'll find it only on composer Howard's album The Hunger Games: Mockingjay Pt. 1 (Original Motion Picture Score).

So if you want musical Mockingjay keepsakes from both Lorde and Katniss, you'll have to purchase them separately.

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