In the almost 20 years since James Cameron first introduced us to the alien world of Pandora, 20th Century Studios has repeatedly tried to parlay the Avatar films’ financial success into a sprawling multimedia franchise. Almost immediately after the first movie hit theaters, there was a video game, plans for a book series that never came to fruition, and announcements for multiple big screen sequels. Despite this blitz, none of those spinoff projects ever really took off, and there is still some debate as to whether any of the Avatar features have had lasting cultural impact outside of (briefly) convincing Hollywood that audiences were eager to see things in 3D.

But the films’ box office totals have given 20th Century Studios a few billion reasons to keep the franchise going. And after years of Cameron hyping up the third chapter of his sci-fi epic, Avatar: Fire and Ash is finally here. Unsurprisingly, the new movie is even more of a visual knockout than either of its predecessors, and you can clearly see how advancements in motion capture technology have enabled Cameron to direct even stronger performances. But whereas The Way of Water felt like the beginning of a new adventure, Fire and Ash plays more like a formulaic sequel that doesn’t have all that much to offer in terms of compelling characters or fresh storylines.

What the movie does have going for it, though, is a lot of the same adventurous energy that has made so many of Cameron’s deep sea exploration-focused projects like Titanic and The Abyss wondrous to see on the big screen. But that energy isn’t quite enough to keep you from feeling every minute of Fire and Ash’s threehour-plus run time. And with the story being so middling, it seems like this would be a perfectly fine place for Avatar to end.

Set shortly after The Way of Water, Avatar: Fire and Ash once again zooms in on human marine-turned-Na’vi patriarch Jake Sully (Sam Worthington) and his wife Neytiri (Zoe Saldaña) at a time when their family is weathering an emotional crisis. Though the Sullys have been accepted into the oceanic Metkayina Clan, they are still racked with guilt after endangering their new community.

Countless Metkayina lives were lost when Colonel Miles Quaritch (Stephen Lang) came hunting for Jake and the valuable substance found in Pandora’s alien whales. No family made it out of the conflict without losing a loved one. The entire clan is in a state of collective grief, but Jake and Neytiri’s pain stems from knowing that their eldest child died in order to save their youngest biological son Lo’ak (Britain Dalton) and Spider (Jack Champion), a dreadlocked human adopted into the Sully family.

Along with its ideas about humanity’s capacity to harm the natural world, the Avatar franchise — which began with a story about a white colonizer cosplaying as an alien before becoming the aliens’ new leader — has always trafficked in a number of tiresome tropes. Though Worthington’s Jake Sully has never been more blue, the character continues to be a quintessential example of the white savior archetype. But one of the more compelling things about Fire and Ash’s central family drama is the way Neytiri’s anger at all of humanity (including her husband) underlines the colonialist fantasy baked into Avatar.

Neytiri and Jake’s beef is far more interesting to watch than the situation with Varang (Oona Chaplin), the pyromaniac cult leader of the new Mangkwan Clan. The clan’s obsession with fire and hallucinogenic drugs make for some fun visuals and explosive set pieces. But compared to the depth Cameron and co-screenwriters Rick Jaffa and Amanda Silver have given to the franchise’s other Na’Vi clans, the Ash people are written surprisingly flat, and they often disappear from the movie for long stretches of time.

Fire and Ash continues to make it stunningly clear that Cameron is one of the few filmmakers working who truly understands how to craft films that benefit from being seen in 3D. Pandora has never looked more gorgeous and like the place you would want to explore. But the stories being told about the planet’s human and Na’Vi inhabitants are beginning to feel more than a little stale.

Fire and Ash is a technical marvel, but at its core it feels like Cameron is still recycling a lot of the franchise’s basics. To really keep this franchise exciting and like a story that could continue for a few more films, Cameron needs to come up with something beyond shiny MacGuffins and chosen ones communing with Eywa as only they can. But if that’s all there is to Avatar, the Fire and Ash might be a good place to stop.

Avatar: Fire and Ash also stars Cliff Curtis, Bailey Bass, Kate Winslet, Giovanni Ribisi, Joel David Moore, CCH Pounder, Edie Falco, Jemaine Clement, Matt Gerald, and David Thewlis. The movie hits theaters on December 19th.