The four arrived to Hong Kong thanks to Aja ship and they landed at the cargo bay where the entrance of the TrollDragons lair is while the civilians are being evacuated from the bridge. Jim then notice something's coming from the fog.

Jim: Guys?

They then notice the jets are flying towards the fog before some may have gotten destroyed.

YN: Could it be?

Soon the volcanic titan reveals itself as its walking on the ocean.

Jim: It's heading for the bridge!

Toby: What do we do?

YN: There's no way I can stop a lava like this.

Just then, Aja receives a call from her communication and she answers it.

Aja: Hold on, I'm getting...(Gasps.) Yes!

YN: What is it?

Aja: You remember the secret weapon? It's here.

They see the wormhole opening and something fell from it which caught the trio attention.

Trio: Is that...?

A giant robot landed on the ocean and faces the volcanic Tiran.

Robot: [I am Gun Robot.]

Toby: Guys, that's him! That's Gun Robot! Oh, my gosh, it's Gun Robot! You see this?

YN: Now thats what I'm talking about! I'd kiss you right now if I could.

Aja: (Shrugs.) Okay.

Aja kisses him which they smile before the robot fires missiles at the titan while the trio got excited.

Toby: Awesomest-sauce!

Jim: But how?

Vex: (Through speaker) Varvatos apologizes for being late. The manufacture of Eli's design took longer than expected.

Toby: Eli designed a whole Gun Robot?

YN: No way.

Toby: Can I keep it and take it to school?

YN: (Serious.) No way.

Toby: Sorry.

Vex: Stand fast. Varvatos is about to reduce this fiery beast...to a smoldering campfire!

Vex fights the titan like pacific rim.

YN: Thats it Varvatos! Kick its lava buttsack!

That was until the volcanic titan knocks the robot towards the bridge. Meanwhile in the lair, Claire's team are still running from the guards as the ceiling is collapsing little by little.

Claire: What's going on?

Blinky: If I were to surmise, the bridge above appears to be collapsing!

Archie: If the bridge falls, there'll be no way out.

They continue to run until Zong-Shi cuts them off.

Zong-Shi: Give me my sphere. I must know my fate!

Claire glances at the relic until she notice it reveal the future.

Blinky: Give it to him so we can get out-

Claire saw what happened next and gasp before it begin to happen.

Blinky: Give it to him so we can get out--

She immediately tackled Blinky before a large rock fell where it could've killed him.

Blinky: That was fortuitous.

Zong-Shi use his tail to knock Claire before she dropped the relic.

Blinky: Mistress Claire!

Zong-Shi grabs the relic and laughs.

Zong-Shi: My future.

Zong-Shi saw his ending before it actually happened by another rock crushing him as his body splattered by it which disgusted the team.

Blinky: By Gorgus.

Thankfully the relic is safe and Blinky picks it up.

Blinky: (Laughs.) And that's why I never read my horoscopes.

Outside of the lair, the robot continues to fight the volcanic titan as it blast laser at the titan before the robot elbow it to its head multiple times.

Robot: [I am Gun Robot. I am Gun Robot. I am Gun Robot.]

YN: Yeah!

Toby: One, two, and three. He's finished.

Robot: [I am Gun Robot.]

Vex: Varvatos loves it when he says that. No evildoers shall be approaching this bridge. Not today. Not if Varvatos and the Robot of Guns have anything to say about it.

Everyone celebrated until they notice the titan is getting back up again.

Aja: Varvatos, behind you!

Before Vex realized, it was too late as the titans lava fist hits the robot chest where the systems are failing.

Vex: Systems failing. Varvatos calmly suggests you all might want to-

Toby: Run for your lives!

The robot crashed at the bridge where it begins to collapse.

Aja: We have to get away from the bridge.

YN: Everybody get close!

They got close to YN who earthbend a stone dome to protect them from the falling debris as Vex manage to retaliate to fire a laser beam from the robots chest. Managing to cut off the titans limb before the titan did the same thing as it hits the robots chest. Back with Claire's team, they're close to the exit as Claire and the dragons are fighting off the guards.

Claire: Blinky, the horngazel! Open the gate.

The volcanic titan begins to melt the robot and thankfully Vex manage to escape with an eject pod. Landing near the four where they meet him.

Aja: Varvatos!

Vex: My queen, we must retreat. The bridge is unstable.

Jim: Claire and Blinky are in there. We can't- I can't leave.

Aja: Jim, it's too late. The bridge will fall.

Jim: Without the bridge, there's no way out!

YN: Get to Claire and the others, I'll try to hold the bridge as long as I can!

Jim nods and run while Toby follows Jim until he stops Toby.

Jim: You don't have to stay, Tobes.

Toby: I'm with you, Jim. Always have been, always will be.

Aja and Vex escape while YN uses his earthbending by stomping his feet couple times to raise the earth to hold the bridge with his strength. Jim and Toby arrive to the entrance and wait for the others.

Jim: Oh, come on, Claire. Where are you?

Blinky uses the horngazel to carve the wall until hit snapped in two where the end of it fell on the other side where Jim and Toby are.

Jim: Oh, no.

Without hesitation, he grabs it and uses it to carve the rest of it way as it burns his hand and he yells.

Toby: Jim, your hand!

That didn't stop Jim until he opens the lair for them to escape.

Blinky: Master Jim!

Jim: Claire?

Claire: Jim!

Claire jumps through and hugs Jim.

Jim: I thought I was gonna lose you.

They then notice the dragons are still holding the guard off.

Claire: Archie?

Charlie: Hurry, Claire. Go, save yourself! I'll keep them at bay.

Claire: Archie, we have to go!

Archie: I have to help him! Tell Douxie I said goodbye.

The gate then sealed itself.

Claire: Archie!

Blinky: Time to go, Claire.

Archie blast the guards away with his fire to save his dad.

Archie: Oh, good heavens. What will I do for an eternity with you?

Charlie: We can play Scrabble, or take over the whole darn kingdom!

Archie: I always wanted a kingdom of my own.

The dragons face off the entire kingdom by themselves. YN still does his best to hold the bridge until the titan destroys it and he fell on his knees from exhaustion after using all his strength to hold it as his friends group up with him. The fall of the bridge caused a huge wave towards them, but luckily Claire use her shadow portal to avoid the wave.

YN: You guys made it.

Blinky: And we have the Krohnisfere.

YN: I just hope its worth it.

From a distance, they see the Aja ship ahead and the akiridion spotted them before they spotted the titan is leaving.

Vex: Where is it going?

Aja: Arcadia.

Time skip

Everybody from each titan they fought regrouped at Arcadia national park except for Barbara and Strickler who are still at the castle. Douxie glances at the relic to see the past where Archie stayed behind with his dad.

Archie: Tell Douxie I said goodbye.

Douxie: I hope he's happy.

Jim: I'm sure he is. He's with his dad.

UN: Don't worry, we'll get him out of there, Douxie. You have my word.

Jim: Arcadia is on the other side of that ridge. We have to stop them here.

Blinky: At least we have the Krohnisfere.

Vex: How does this bring us victory? Do you bludgeon your foe with it?

Toby snatches it from Vex.

Toby: Sort of looks like a blinged-out Magic 8-Ball.

Jim grabs the relic and looks at it.

Jim: How is this supposed to make things right?

Blinky: I...don't know.

Toby: If only Nari were more specific.

Douxie: Let me talk to her. I need to try again.

Nomura: She's fused with that Titan.

UN: It almost killed Nomura.

Douxie: I was inside her head once before. I can do it again. But I need to be with her.

Jim: You will. And you won't be alone. Aja, where is Nari right now?

Aja pulls out the map to locate Nari.

Aja: Ai-yai-yai.

Claire: She's at Chihuahua Mexico.

Jim: Then that's where we're going.

Toby then notice YN stayed silent as he glances at the landscape.

Toby: Hey, YN. Whacha doing?

YN: Maybe we don't that Krohnisfere for this.

Jim: What do you mean?

YN: I have an idea. We can ambush the ice titan over there.

YN points at the gap where it looks like a pathway for a titan.

YN: But we need to keep it down as long as we can before I use my plan and its gonna require two earthbenders.

UN: What do you need?

YN: Aja, do you or Vex have anymore explosives like the ones we tried to use against the ice titan?

Aja: Just a few.

Vex: But enough to make the world shake by Varvatos might!

YN: Good. Here's the plan.

Time skip

After YN shared his plan, Douxie, Claire, and Jim arrive to Nari location which they're on the titans shoulder thanks to Claire's shadow portal.

Douxie: Nari!

Nari didn't response.

Douxie: Nari?

Jim: She can't hear you.

Douxie: I have to believe you're still in there, Nari. If you can hear me, please, give me a sign.

Suddenly the vines grabs the three by surprise as its about to drop Jim and Claire off the edge.

Claire: Jim!

Jim: Hurry, Douxie!

Douxie: Oh, no, no. That's not a good sign.

Douxie prepare his magic as he tries to reach for Nari.

Douxie: Blast it, Nari. Fight it!

Claire: Douxie!

Douxie presses on as he's close to reach Nari grasp.

Douxie: I'm staying with you, no matter what.

Douxie grabs on Nari hands and uses his magic.

Douxie: No more running, remember? No more running.

Nari: No...more...running.

Douxie successfully frees Nari from the curse as the titan stops.

Nari: Douxie?

Douxie: Nari.

Nari: Where am I?

Douxie: You're with us.

He hugs Nari tight.

Douxie: You're with us.

Jim: Nari, we have the Krohnisfere, but we don't know how to make the tennth Configuration. How does it make it right?

Nari: Trollhunter make Ninth Configuration. Krohnisfere will make right.

Jim: Please, Nari.

Nari: Time unfolds differently, like a flower. Only Trollhunter will know.

Jim: That doesn't make any sense.

Douxie: Well, at least we have Nari now.

Nari: No, you have a Titan.

Jim: Yeah, a Titan miles away from the other Titans.

Claire: Not for long. I know how to get you there.

Jim: No, the Titan is too big.

Douxie: Jim's right.

Claire: But we need Naris help for YNs plan. Don't worry, I can do this. One more time!

Meanwhile the class of Arcadia arrive at Arcadia national park from a school bus for a trip as theyre viewing the whole landscape.

Lawrence: (Sighs.) Here we are.

Girl: Hey, coach. Is this place safe?

Lawrence: Of course. You'll all be thanking me. There's absolutely nothing all the way out here. Yeah, not even reception.

Suddenly the kids felt a rumbling.

Girl: Uh... what was that?

Her glasses begins to freeze.

Girl: Hey, my glasses! Coach?

Coach Lawrence is distracted by his phone until he felt the cold.

Lawrence: Oh, it's getting kind of cold here. Ooh, ooh, I got a bar. Ooh, two bars. Two!

Suddenly he notice the ice Titan walking over them which they all freaked out.

Lawrence: We're going back to the city, where it's safe!

The ckass got back ti the school bus and runs off while the titan continues to walk where it reaches to the gap as the trollhunters and akiridion spotted it.

Toby: Guys? It's coming!

Blinky: Great Gronka Morka!

Toby picks up the walkie talkie to contact YN.

Toby: YN, now would be a good time.

YN: [We can't! If we do it, it'll only take half of it before it rebuilds itself! We need Naris help!]

Soon the trio arrived and Claire uses her magic to open a massive shadow portal thats big enough for Nari titan to pass through and faces Skrael.

Skrael: Nari!

Nari attacks Skrael with her titan.

Skrael: Nari, what are you doing? How did you slip from our control?

Nari: My friends set me free so I can stop you!

Nari punches Skrael couple times until she uses the vines to grab and toss him to the cliff side. Skrael retaliate as he grabs and rips off the large piece of stone to use it as a weapons where he knocks Nari away with it.

Claire: Nari, get up!

Blinky: Look out!

Jim: Nari, get out of the way!

Nari gets up and rams Skrael like a bull where she successfully knocks Skrael back and falls on the gaps before she uses the vines to pin down the ice titan. Toby contacts YN to signal him.

Toby: She got him where we wanted!

We see YN and UN are each standing on the cliffs.

YN: Now, uncle!

Both the earthbenders use their powers where YN uses his lava bending and his uncle sinks Skrael Titan to the ground to keep it down as the lava appear on the ground. Once YN created enough lava that surrounded the titan, he picks up the walkie talkie.

YN: Detonate the charges now!

Aja and Vex detonate the charges that were attached to the wall. Once it all exploded, it caused the lava to fall down on the Titan as it melts and weakening Skrael magic due to the heat. YN yells as he gives everything he's got to have the lava cover the titan to ensure it completely melts. Everyone cheers for the ice titan defeat as YN collapse before his uncle caught him while the lava did the rest of the job.

YN: I'll live.

UN: You did good, YN. All that bending by yourself proves that you're the strongest earthbender in the world. You're parents will be proud.

YN: Thanks, uncle.

YN then notice Skrael is trying to escape but he seems to be stuck on the ice debris. He heads down to where Skrael is and place his Skrael chest as he holds out a boulder over his head with his remaining strength.

YN: Next time better watch who you're messing with. You'll regret it before your get crushed.

YN crushed Skrael with the boulder before he uses his bending to put out the lava. Once he's done, he sat down to the ground before everyone arrive with Nari's help since Claire exhausted her magic.

Aja: You did it!

Blinky: Great gronka morka! I've never seen a powerful earthbender to take on a titan in my entire life!

Toby: You actually did it! You stop the Titan!

YN: No, we did it. We couldn't have done it without each other.

Jim: And we stopped them from uniting.

Suddenly Aja gets contact from her brother to share the unfortunate news.

Krel: [Apparently the Fire Titan did not get the memo.]

Aja: Seklos and Gaylen.

Claire: What?

YN: It's still marching?

Krel: [It's approaching Arcadia.]

Jim: But why? The three can no longer unite. Blinky, you're sure you read the grimoire right?

Blinky: Of course. "When the three unite, Earth will be reborn, back to the age of first creation," you see?

Jim notice something and he splits the paper that are stick together. Revealing a hidden page this whole time. Causing Blinky to gasp before Douxie reads the hidden page.

Douxie: "But if only one succeeds..."

Blinky: "That will be the element from which the world will be reborn."

Toby: You forgot to turn the page!?

Blinky: It was stuck and moldy.

Toby: And you didn't notice? You've got six eyes!

Blinky: The world was ending. I was rushed!

Douxie: That's why the Titans came to Arcadia. They didn't have to unite with each other. They have to unite with the Heartstone.

Blinky: That actually makes horrible sense. The reason all of these trolls, extraterrestrials, wizards happened to come here is because under Arcadia is the only surviving primordial Heartstone! As I said, Arcadia is the center of the universe.

YN: (Groans.) Can't they all just take a five minute break?