Grade: B

Well, you can’t say that Matt Reeves isn’t upfront about it. At one point in “War for the Planet of the Apes,” the director focuses on words scrawled on the wall of an underground tunnel, and they read “Ape-okalypse Now.” It’s a not-so-subtle message that the picture is fundamentally a “Planet of the Apes” version of Francis Ford Coppola’s Vietnam classic, which itself was an adaptation of Joseph Conrad’s famous novella. As it turns out, it’s a good one.

Not that the film, co-written by Reeves and Mark Bomback, doesn’t show other influences as well. The initial section is basically a revenge story, modeled after Westerns like “The Bravados” or the Sergio Leone spaghetti variants, about an individual tracking the person who killed his family In order to even the score, though here he’s not a solitary avenger. And the final chapter is modeled after a film like “The Great Escape,” though without that movie’s lighter elements.

Of course, there’s one major difference between “War” and all those cinematic influences: the hero in this case is a chimpanzee rather than a human. Indeed, the humans are unquestionably the villains.

That’s the inevitable trajectory of the series that began in 2011 with “Rise of the Planet of the Apes” (directed by Rupert Wyatt) and continued in 2014 with Reeves’s “Dawn of the Planet of the Apes.” Those films related how unwise scientific experiments gave rise to the Simian Flu, which wiped out much of humanity but led to accelerated evolution among monkeys, some even developing the ability to speak. One of those was Caesar (acted, via increasingly impressive motion-capture technology, by Andy Serkis), who led an uprising that, in the second installment, resulted in a conflict between him and the brutal Koba (Toby Kebbell), who wanted to wipe out the remaining humans while Caesar espoused a philosophy of peace and, perhaps, coexistence.

Now, he and his community—including his wife Cornelia (Judy Greer) and sons Blue Eyes (Max Lloyd-Jones) and Cornelius (Devyn Dalton)—have established themselves in an enclave deep in the forest. Unfortunately, a squadron of human soldiers has penetrated the district, intending to wipe them out. Caesar’s forces fend off their attack and send the survivors back as a sign of their desire to avoid further conflict, but the leader, the otherwise unnamed Colonel (Woody Harrelson), orders another assault, during which he hopes to kill Caesar but massacres his family instead.

Torn between the responsibility of leading his tribe to a safe new home and seeking revenge, Caesar decides on the latter, intending to go off alone to confront the Colonel. But others insist on accompanying him: his ever-loyal aide Rocket (Terry Notary), gorilla Luca (Michael Adamthwaite) and wise old orangutan Maurice (Karin Konoval). Along the way they add two outsiders to their number: Nova (Amiah Miller), a mute human child, and Bad Ape (Steve Zahn), a talking chimp who has been hiding in the wild since escaping the zoo. They eventually make their way to the Colonel’s compound, where some of them fall into his hands and are herded into huge cages where apes are kept to serve as workers constructing a huge stone wall. As portrayed by Harrelson with a bald pate, the intense, brutal Colonel is clearly modeled on Marlon Brando’s Kurtz from Coppola’s film.

What follows will not be revealed here, but it involves not only escape, but a revelation of the purpose behind the Colonel’s wall. All will culminate in a battle in which Caesar plays a major role amid man-made and natural disasters, and the Colonel meets a poetically just demise—which also presages the end of humankind as the dominant species on earth.

Reeves’s film is definitely a big-budget summer special-effects spectacular—and a very good one—but a remarkably somber one, using tropes from films past to deepen the series’ dark message about treatment of ‘the other.’ One can, of course, dismiss that message as glib when transferred to a tale of human versus ape, but it’s nonetheless noteworthy that it should be delivered by a major studio release in the popcorn movie season at all.

And whatever your opinion on that score, it’s undeniable that from a technical perspective, the film is a marvel. Serkis’ Caesar is a remarkable fusion of acting and effect, giving the character a degree of realism that poor Roddy McDowall could only have dreamed of when he played Cornelius wearing a rubber mask decades ago. The other simians are equally impressive, with Konoval’s Maurice and Zahn’s fidgety Bad Ape especially so, though Notary’s Rocket, Adamthwaite’s Luca and Ty Olson’s Red (a gorilla who has defected to the Colonel) nearly as fine. Among the humans, Harrelson dominates as the manic military man, but Miller is a suitably angelic and Chavarria brings an undercurrent of uncertainty to one of the Colonel’s minions.

The picture excels in every technical aspect. Not only are the visual effects overseen by Joe Letteri and Dan Lemmon outstanding, but James Chinlund’s production design and Michael Seresin’s haunting widescreen cinematography create a mood of palpable dread, accentuated by the deliberate pacing of editors William Hoy and Stan Salfas. Michael Giacchino contributes an unusually effective score which suggests Jerry Goldsmith, especially in the early reels.

Most movie trilogies experience a fall-off in the final installment, but “War of the Planet of the Apes” maintains the high quality of the first two episodes, bringing the story to a solid, if preordained, conclusion in a narratively imaginative fashion. It would seem a logical end point that leads quite naturally toward the 1968 original (and even toward Tim Burton’s misguided 2001 remake); but Hollywood being what it is today, if “War” proves a hit, there will doubtlessly be further chapters. The makers would do well to remember the unfortunate effect such undue prolongation had on the first series, which finally ended with a very bad TV incarnation that barely managed a single season. No need to repeat that humiliation; stop while you’re ahead.