WARNING: The following contains spoilers for Trollhunters: Rise of the Titans, now streaming on Netflix.
Trollhunters: Rise of the Titans brings Guillermo del Toro's Tales of Arcadia franchise to an end, which connects the television series Trollhunters, 3Below and Wizards. Now, all the heroes have to unite to stop the Arcane Order, evil gods, from raising three Titans to purge the planet for a rebirth.
Admittedly, it's tricky as Jim's mystical Trollhunter amulet is broken, which means that he can't be the key to stopping the giants. However, the team works around it, and while they devise a solid strategy, it results in a lot of chaos and loss of life that causes Jim to engage in a mind-bending finale.
Two Titans Fall
The Titans are coming to Arcadia, which is the center of the universe, but the heroes need a Khronisfere (a time orb), as well as the Trollhunter to unlock something called the Ninth Configuration. However, they improvise with Douxie helping to break Nari, the Earth elemental, out of her brainwashing. She's been trying to help them win the war for some time, but it only enrages Skrael, the Ice elemental, who brought the Ice Titan from Greenland.
Both battle after Nari's giant comes over from Brazil, and sadly it ends with both Titans stabbing each other. The gods were connected to them, so their essences disappear, but there's still trouble looming as Blinky made a mistake deciphering the prophecy. He thought three Titans needed to unite, but actually, once one reaches Arcadia's heartstone, its nature will be what rebirths the Earth. This means Bellroc's Fire Titan from the Chinese ocean will cause the planet to burn with volcanoes blowing up and lava washing life away.
The Final Battle
Luckily, Jim realizes the configuration is his crew: nine brave soldiers, who help him pull Excalibur from Merlin's stone in Arcadia. He then sends the extracted stone for Stuart to use to rebuild his amulet. Jim then heads atop the golem to fight Bellroc but without the Trollhunter armor and powers, he's struggling with Excalibur. Luckily, the amulet's powered up again and finds him, but Jim is wounded badly.
However, Toby has a secret weapon in his van as they earlier rigged a reactor that uses Akiridion tech from Krel and Aja's alien world so it can temporarily nullify magic. He then creates a blast that takes away Bellroc's magic, allowing Jim to slash and kill the god. It results in the Titan falling down to Earth, but it's a bittersweet ending as Toby's crushed.
Jim's Time Trip
It cuts celebrations short, and when Jim finds Toby, his bestie admits he's just proud to have been there at the end, as they always promised. Toby dies, leaving Jim heartbroken over all the other allies he lost in this film. He then remembers Nari's ominous warning about the time orb and cracks it open with Merlin's sword to find the time stone. Jim deduces that "making it right" means he'll have to travel back in time to start their journey over.
He says goodbye to everyone who agree that if fate has it, then they'll all meet again, but under victorious circumstances as Jim would have the intel to ensure that they win the wars but emerge alive. It's a risk but worth it in Jim's eyes, so he binds with the time stone and travels back. He wakes up at the start of the Trollhunters series, and embraces Toby.
He then starts seeding out a path that changes their history, moving in on romancing Claire early, and even bonding with his mentor Walter and getting him to fall for his mom, Barbara, all so Walt (a changeling) doesn't become a villain. Most of all, he sends Toby down the canal from the premiere, telling him he'll find something unique. This is where Jim found the amulet, and as Toby finds it and it speaks to him, he's deemed worthy to become the next Trollhunter in this new timeline.
Trollhunters: Rise of the Titans, based on Guillermo del Toro's Tales of Arcadia trilogy series, is now streaming on Netflix.