Jennifer Lawrence returns as Katniss Everdeen for the first part of the finale in “The Hunger Games: Mockingjay — Part 1.” (Murray Close/Associated Press via Lionsgate)

By definition, “The Hunger Games: Mockingjay — Part 1” is only half a movie.

As the first part of the last installment of the juggernaut adaptation of the wildly popular young-adult novel, this dutiful, glumly atmospheric placeholder feels like a long, extended inhale: a collective “Here we go” before the last triumphant hurrah.

As the movie opens, the series’ heroine, Katniss Everdeen (Jennifer Lawrence), is being held at a rebel outpost in District 13, where precinct president Alma Coin — played by Julianne Moore with silver-haired seriousness — is seeking to galvanize the remaining districts to overtake the capital city and rid the nation, Panem, of its fascistic leader, President Snow (Donald Sutherland).

Katniss, having just destroyed the sadistic Hunger Games by way of her steady aim with a bow and arrow, is the obvious choice to rally the rebels. As Plutarch Heavensbee (Philip Seymour Hoffman) keeps insisting to Coin, Katniss has just the “anger-driven defiance” to be the perfect face of the burgeoning revolution.

The choice of words is meaningful: Although there are some explosive battles and grisly scenes of their aftermath in “Mockingjay,” the war is primarily fought by way of televised pronouncements and carefully choreographed electronic propaganda. When an early attempt at an inspirational video featuring Katniss falls flat, she winds up doing an extended video opp — much like an electronic press kit for a movie like “Mockingjay” — by visiting a field hospital, receiving a welcome one might expect for Eleanor Roosevelt or Joan of Arc.

"The Hunger Games" continues to set the world on fire with "The Hunger Games: Mockingjay—Part 1." Directed by Francis Lawrence, Everdeen fights to save Peeta Mellark in this film based on a novel that is the third in a trilogy written by Suzanne Collins. (Lionsgate)

As a charismatic figure, Katniss is a singularly reticent and unsmiling one: She’s uncertain whether the allies she made during the Hunger Games have all died, and she’s in particular mourning for Peeta (Josh Hutcherson), from whom she became separated during the last chapter. Even her best friend, Gale (Liam Hemsworth), can’t seem to shake her out of her lugubrious mood. One of the only seemingly spontaneous moments in “Mockingjay” occurs when Katniss travels to her ravaged home in District 12 to retrieve her beloved sister’s pet cat.

“You’re breakin’ my heart,” she mutters when she stuffs the squalling creature into her bag. It’s just the kind of irreverent line that one would expect from Lawrence, the bold, often recklessly unpredictable young actress who has become fused with the literary heroine of a generation. As ever, Lawrence is not only the best thing about “Mockingjay,” but also probably the one thing that makes an otherwise dreary, derivatively dystopian franchise worth watching. Even trudging through the post-industrial carnage and underground bunkers of the film’s blighted universe, she radiates unaffected humanity and light.

That’s all the more remarkable considering how much time she’s forced to spend crying, scowling and looking steely-eyed into cameras — which, as in Lawrence’s real life, are omnipresent. Like the actress herself, Katniss isn’t one for cutesy, canned promo shots. But she knows the value of projecting the right persona. Even though her stylist, Cinna (Lenny Kravitz), is no more, Effie Trinket (Elizabeth Banks) is on hand, a bit more drab for the wear, but armed with cool designs for Katniss’s next incarnation as the messianic icon of a new world order. “We will make you the best dressed rebel in history,” Effie coos. “Everyone’s going to want to kiss you, kill you or be you.”

Such is the stuff that all girls’ dreams are made of.

Perhaps the cleverest feat of the “Hunger Games” epic has been to marry so seamlessly the shallow values of our own image-driven culture, the virtues of fashion at its most self- expressive, classic anti-authoritarian political ideals and the irresistible, ungovernable force that is female adolescence. Lawrence’s Katniss is the perfect foil for all four, her raw-boned beauty, strength and steady focus just as compelling, at their most unadorned, as when they’re tricked out for maximum stage presence.

Directed by Francis Lawrence from a script by Peter Craig and Danny Strong, “Mockingjay” gains steam as it goes. Its retro-futuristic aesthetic lacks the flamboyance of past installments, but possesses its own grim integrity, and even contains one authentically shocking reversal that bears more than a whiff of a “Manchurian Candidate”-like menace. It’s a joyless, surpassingly dour enterprise, but one that fulfills its mission with Katniss’s own eagle-eyed efficiency and unsentimental somberness. “Mockingjay” sets up the end Game with a grim sense of purpose.

★ ★ ½

PG-13. At area theaters. Contains intense sequences of violence and action, some disturbing images and mature thematic material. 123 minutes.