The “Divergent” series — a derivative saga of family, factions and overstressed females — soldiers within sight of the finish line with its third installment, “Allegiant.” But a story that kicked off two years ago at a reasonable gallop has now slowed to barely a limp.
The first film in a two-part finale (the second, “Ascendant,” is expected next year), “Allegiant” sends Tris (Shailene Woodley), her brother, Caleb (Ansel Elgort) and her hunky squeeze, Four (Theo James, even more expressionless than usual if that’s possible), fleeing from a still-walled-in Chicago. One shower of toxic rain and a blasted landscape later, they wash up at the gleamingly pristine Bureau of Genetic Welfare, where David (a smugly sinister Jeff Daniels) presides over unspecified hanky-panky with the human genome.
Spouting biological balderdash with a commendably straight face, David declares Tris “pure,” a designation that comes with all-white outfits and an all-access pass to David’s private aerie. (This doesn’t sit well with Four, who, being “damaged,” is stuck below, wearing Mad Max’s postapocalyptic castoffs.) Ill-defined and padded with tame special effects, these scenes are so lacking in narrative momentum that we can almost hear the hum of a plot idling in neutral.
Tris, too, seems becalmed and unsure, vacillating between David’s professed humanitarianism and Four’s insistence that evil is afoot. Ms. Woodley, previously such a strong anchor for a series that’s casually dominated by powerful female characters, feels disengaged here and a little tired. And a sidelined Octavia Spencer, playing the leader of the former peace-loving Amity faction — now reborn as a resistance group known as Allegiant — appears similarly detached.
A flaccid blend of eugenics, purloined children, memory-wiping gas and laughably unlikely scuffles, “Allegiant” (directed by Robert Schwentke) offers a weak bridge to the series’ conclusion. Whether audiences will still be allegiant after crossing it remains to be seen.
“The Divergent Series: Allegiant” is rated PG-13 (Parents strongly cautioned). Body slams and lip locks. Running time: 2 hours.