Divergent and its sequels don't make a whole lot of sense -- but what they do have is a blend of wish-fulfillment, anarchic WTFery and actual social commentary that amounts to the Platonic ideal of "dystopia as fairy floss". You will be in a sugar coma at the end of this film, but the sacrifice of your brain may not be entirely in vain. Spoilers ahead...
I never got around to reading the books by Veronica Roth. So I'm largely assessing these films on their own merits, rather than looking at whether they do justice to the books. I've heard the books are fun, but I also believe the movies should stand on their own.
The Divergent series takes place in a post-apocalyptic world where Chicago is a walled city, and the rest of the world is mostly a blasted ruin. Inside Chicago, everybody gets sorted into five "factions", depending on which personality trait you display: Bravery, honesty, humility, intelligence or friendliness. But Tris Prior, our hero, doesn't fall neatly into any of those groupings, because she's Divergent.
The first movie in the series was a fun, entertaining romp that managed to make some interesting points about the danger of stereotyping people according to their jobs. The second film, though, got mired in navel-gazing and bad CG effects, as everybody obsesses about Tris' mental state until at last she takes a weird cyber-tentacle test designed to prove that she's the ultimate Divergent.
In this third movie, everybody's learned the truth: Chicago was some kind of experiment, of which Tris, as the most Divergent person, is the ultimate result. And somewhere outside the walls of Chicago, the people who created this bizarre system are waiting to meet her. In this third movie (which I'm told is based on the first half of the third book in Roth's trilogy) the story is half about the chaos in Chicago, now that the old faction system has been destroyed, and half about Tris encountering the people who decided it was a good idea to turn the Windy City into a bonkers social experiment.
The good news? Despite being based on only half a book, this movie has a reasonably cohesive storyline, with a beginning, middle and end. There's a decent progression, and there are clear stakes, and some of the characters have a real arc over the course of the movie.
The bad news is that the story doesn't make an over-abundance of sense, and a lot of the plot developments manage to be both logic-defying and predictable. Every few minutes, another reveal comes along, turning everything on its head, and the characters begin to look as bewildered as the audience. Also, the main storyline of this movie relies on a theory about human genetics that would probably make a Year 3 student laugh.
But the plot is really just a scaffold on which to hang a gauzy fabric of wish-fulfilment -- in this third movie, as in the second, Tris Prior is the centre of the universe, and everything revolves around her. She's not just the "chosen one", in the classic Luke Skywalker/Buffy mode, but she's also everyone's moral compass and the person whose very existence is the linchpin of social change. And the themes of social control are back, even stronger than ever, as Tris confronts a never-ending parade of authority figures who want to make everybody conform. The ultimate fantasy of Divergent isn't just to be the one unique individual in a sea of sheep -- it's to have the power to rescue everybody else from conformity, too. Which is kind of sweet, and kind of sociopathic.
Shailene Woodley wanders through the movie's endless pulled-from-a-hat set pieces, looking doe-eyed and yet resolute. Her giant brown eyes get wider and wider the more incomprehensible pieces of backstory she's forced to absorb, and Woodley's capacity for tender surprise is the miracle engine of these films. Miles Teller, who was just sort of an annoying gadfly in the first two movies, steps up and becomes the snarky Greek chorus -- he's the only one who's allowed to crack jokes in these movies, and he takes full advantage. Not that he's actually funny, but at least having one character who knows how absurd it all is helps a lot.
Meanwhile, though, director Robert Schwentke does a somewhat pedestrian job -- this movie suffers from the same dichotomy that haunted the first two Divergent films, only worse. Most of the time, the characters are filmed in somewhat static close-ups and group shots, with most of the action sequences feeling run-of-the-mill and occasionally hard to follow. But when it comes time to unveil some computer-generated eye-candy (a post-apocalyptic landscape, a futuristic outpost, some other miracle) the frame suddenly gets bigger and the movie becomes visually interesting. Schwentke never figures out how to integrate the eye candy -- which is lovely -- with the rest of his film.
Ultimately, the incoherence of the Divergent series is a feature, not a bug. This is a series about a bewildering world, in which adults are constantly telling teenagers contradictory (and self-contradictory) information. People are always trying to pigeonhole you, and only you know how special you really are. In other words, Divergent, with all its incredible flaws, may be the most perfect distillation of the horror of adolescence.
And part of what makes me want to forgive Allegiant, in particular, for being a godawful mess is that it does come to a conclusion that has something new to say about the series' main theme of social control. This time around, the villain's scheme is a new spin on the notion of controlling your identity (I won't spoil what it is, though). And the idea that identity, itself, is your biggest weapon against oppression -- knowing who you are, in other words -- comes up in an interesting way.
Bottom line: Allegiant is much more entertaining than the second movie in the series, where everybody just wanted to know how Tris was feeling for two hours. This time around, it's more like everybody is telling Tris crazy shit for two hours, and then there's a big fight. I recommend seeing Allegiant with your intoxicant of choice, especially if you haven't seen the first two movies in the series. Because the less you understand what the heck is going on in this film, the closer it probably gets to its ultimate potential for delicious sugary WTF.