When they team jump through the rift, they finally made it back home.

Douxie: Welcome back to the 21st century!

YN: Finally, I think I've had enough of time tour for one life.

Steve: Ah! Sweet, sweet pollution. How I missed you! (Phone chimes.) And reception! Hot dang! So many messages.

The three were then interrupted when they hear Jim yelling because of the shard in his chest.

Claire: Jim! Hold on, please!

Steve:  Man, oh, man! Can this get any worse?

They see the the Camelot is falling down.

YN: You just had to open your mouth, Steve. Douxie, we gotta get our friends out of there before they hit the ground.

Douxie: I'm on it.

Douxie navigate the ship and fly near the castle for the rest of the team to arrive and meet everyone.

Douxie: Need a lift?

Archie: Douxie! But you're trapped in the past!

Douxie: Not anymore.

Merlin: Took you long enough.

YN: Don't push it old man.

Merlin: Nevertheless, we have much to talk about.

Toby: Oh, no, Jimbo! What's happening to him?

Claire: The shard, it's moving to his heart.

Douxie: I'm getting everyone home safe, as promised.

Merlin: Not yet! We're missing one!

Nari: Merlin!

Nari is the last to jump on the ship before Douxie gets them out of there. A large piece of the castle is falling right towards them.

Blinky: Incoming!

YN: Aarg, give me a lift!

Aarg nods before he grabs and throw YN for him to destroy the piece of the castle with his fist to clear a path. Thankfully YN still has the chains to swing his way back on the ship while some of the castle pieces fell down and destroy the entire school before they landed near it.

Steve: (Chuckles.) I guess school's out for the ever. Aw, man, I never cleaned out my locker!

Nari: Your beautiful school home was crushed.

Toby: So now that we've cheated death, quick Q. Who's the little magic plant lady?

Merlin: Nari. She renounced the Arcane Order and sought asylum in Camelot.

Everyone get off the ship but Jim still feels pain from the shard as he yells.

Claire: Jim! Hold on!

Nari: Poor soul. Your corruption...

Nari tries to use her powers to save Jim but to no avail.

Nari: (Gasps.) I feel it worsening!

Aarg: Jim hurt. Dying.

Douxie: There has to be something we can do.

Merlin: I told you nine centuries ago,
there isn't.

Douxie: (Surprise.) You remember what happened?

Merlin: Like it was yesterday, which, for you, it was. I know it was a hard choice, but you did the right thing for the sake of the world.

Suddenly the arcane order is near with its own floating castle. 

Claire: We've gotta get him out of here!

Claire helps him up but Merlin stops her.

Merlin: Stop! The shard's creeping towards his heart again!

Bellroc: Nari, come back to us and finish the work you have begun!

Skrael: You misunderstand our grand vision.

Douxie: They are under our protection.

Claire: If you want them, you've gotta get through us!

Everyone prepares to fight the arcane order.

Bellroc: So be it.

They send in the GreenKnight to face the Trollhunters.

GreenKnight: Nari, Trollhunter, you are mine.

They fight the knight, but were quickly overpowered even with the wizards help.

Merlin: We're outmatched! Everyone, fall back!

Douxie: He's unstoppable.

YN: We have to lose them first!

Jim realize about the shard when the last time he accidentally force it deeper and remembers what happened. And so he took a big risk with and idea.

Jim: We need an edge. I'm sorry, Claire.

Jim forces the shard in him and he screams as everyone saw it.

YN: Jim, what are you doing!?

Claire: No! You can't! Jim!

Jim: It's the only way!

Claire: No! No, Jim!

Blinky: No, Master Jim!

The shard did its job and it turns Jim into a full troll creature as he roars.

Jim: Run!

Jim charges at the knight and holds him off.

Claire: No! Jim!

Douxie: We have to go! He's buying us time!

With no other way, they fall back. But at a cost of loosing their ally who's not being controlled by the green knight with the sword. But that didn't stop the order from finding Nari. As they hide, Claire desperately want to go save Jim but Douxie and YN stops her.

YN: Claire, don't!

Douxie:  There was nothing we could do! We'll go back for him, I promise.

Merlin: We can't. We must hide Nari. There's more at stake than you know. The Trollhunter-

Claire: Don't you talk to me about Jim!

YN: Guys, this isn't the time.

Blinky: Oh, Master Jim! We are lost without him. We must seek refuge to regroup, form a plan to save him.

Merlin: Where? The Order has roamed this planet for centuries. They know all my places of power.

Douxie then notice an electronic store nearby and gets an idea.

Douxie: I know a place with plenty of power where the Order's magic won't find us.

They all head to the store called Hex Tech where they meet Douxie friend name Zoe and surprisingly Krel in the store as a customer.

Douxie: Zoe! (Chuckles.) We need a place to lay low.

Zoe: Hisirdoux Casperan! You have a lot of nerve.

Krel: Yes, like cutting in line.

Zoe: We were supposed to hunt niffins and get burgers, remember?

Krel: And you are supposed to help me with my problem, remember?

YN: Krel, what's up?

Krel: YN, Toby? What are you giys doing here?

Toby: Evil wizards shot down our time-traveling castle and stole Monster Jimbo!

Zoe: Ugh. Come on, let's head to the back.

Zoe opens the door which is like advance technology door.

Steve: Whoa! Magic door!

Merlin: What are we doing here? We're not safe in this toy store.

Zoe: (To Douxie.) Yeesh! You brought your boss here? (To Merlin.) We're closed to privileged Arthurian toolbags.

Merlin: (Chuckles.) No.

Toby: Come on, Krel. We're on a mission.

Krel: Wait! Seems I missed a lot.

YN: I'll fill you in on the way. But um, how's Aja?

They all enter the hallway while Zoe speaks.

Zoe: Welcome to the real Hex Tech. Back here we charm the mortals' electronics into shape and use the cash to fund our own mystical pursuits.

This impress Krel to see the workers using magic to fix tech.

Archie: Hex Tech is run entirely by underground hedge wizards.

Zoe then leads them to a room where everyone can stay for the time being.

Steve: (Gasps.) Dude, this place is sick!

Krel: Was that an antigravity ray?

Zoe: (To Douxie.) You guys should be safe here. I have to go back. Do not break anything.

Zoe leaves to go back to work while the team figure out a plan.

Toby: Anything in here that can stop some ancient evil wizards? It'll be nice to have a moment to catch our breath.

Merlin: If the Order has their way, we won't be breathing at all. Nari, tell them what we're up against.

Nari: Since the beginning, the Order has always sought to protect the balance of magic and mortal, no matter the cost. But our actions only brought pain.

YN: Oh yeah, we definitely learn that the hard way.

Claire: No kidding.

Merlin: I've spent a millennium keeping their horrors at bay. But it wasn't enough.

Nari: Bellroc and Skrael believe humanity is lost, beyond correction. Now they wish to end it all. They search for the Genesis Seals.

Claire: What are the Seals?

Steve: Cute but deadly sea mammals, duh.

Douxie: (Chuckles.) You wish. It's the oldest tale in the wizards books. Primal seals that contain the very essence of magic.

Merlin: If the Seals are broken then raw, uncontrolled magic shall rise upon the world, wiping it like a flood.

Krel: Come on! Destroying the world? Again?

YN: (Deep sigh.) Screw this. I need a drink. (Leaves.)

Toby: Ugh, can't these bad guys just remodel a continent or do something nice for once?

Nari: All of the Arcane Order must be present to open the Seals. That is why I fled.

Merlin: I've hidden the Seals away, but we must keep Bellroc and Skrael away from them and Nari, or it is the end of all things.

Claire: But if they're after her, why do they need Jim?

YN: (Digs through the fridge.) What does it matter? What matters is that they didn't kill Jim.

Blinky: Which means there's a chance to save him from corruption. We must search the source of Master Jim's corruption.

Krel uses the laptops to search for any possibility.

Blinky: Try "Rasputin Theurgy."

Krel: Nothing.

Blinky: Let me see that.

Krel shows the laptop to Blinky.

Blinky: Curse you, auto-correct!

Merlin: I empathize, Miss Claire, but we cannot go back to save him.

Claire: Come on, this is our friend we're talking about! Your Trollhunter! You want us to just forget about him? No way!

Douxie: Surely there's something that we can do-

Merlin: The risk is too great for a rescue! We must keep Nari safe from the Order. The fate of existence is at stake!

Toby: This is why nobody likes you, dude!

Merlin: I care not for your "likes." James Lake is corrupted, gone! There is no bringing him back!

Claire: Or you're just too stubborn to try!

YN: (Shout.) ENOUGH!

YN slams the table with his fist and destroys it where it made everyone silent.

YN: You two are trying to driving me crazy for the last god knows how long because of your lousy choices!

Claire: Lousy!?-

YN: Shut it! Don't act like you're free from blame! You pushed us to risk everything to save your brother from the darkland and freed Gunmar! And now you want to rest the world to save Jim from the most dangerous witches who wants to bring hell in the world.

Merlin: That is correct-

YN: And you! Don't even get me started with you! You risked the world by freeing Morgana and allow the gumm-gumms to attack so you can get your magic back and make matter worst, turn my best friend into a troll! The only reason we got lucky is that we gave everything we got! And still the bad guys throws everything at us! You two may have solid points, but not making the right choice!

YN pants and catches his breath while they both stayed silent until Nari speaks.

Nari: My presence causes such discord. I have put you all in danger.

Steve: No worries, veggie lady. You are under the protection of the Knights of Arcadia, which is only me, currently.

YN catches his breath before speaking calmly.

YN: I understand what you two are trying to do. But we can't jeopardize the whole world for our friend. (To Claire.) He's not just your boyfriend, (To Merlin.) he's not just your Trollhunter, he's my best friend, a brother to me. I know it's the risk he would do to save one of us. So we'll find a way to save my brother.

Claire: (Surprise.) Really.

YN: But understand this and understand it well, I don't take this choice lightly as any of you. But I know its the right choice. Not an easy one, but a right one. What we need is a plan. But we don't know how long we have to form one.

Claire: There's gotta be one. Come on, back me up, here! Anybody? Archie?

Archie: Don't look at me. Cats don't have the right to vote. Neither do dragons. Yet.

Douxie: Wait a tick. I know a way we can rescue Jim without risking the world.

Merlin: Is that so?

Claire: How?

Douxie: And if it works, it will be quite the little magic trick.

Time skip

Merlin: I have concerns about this cockamamy plan of yours.

Merlin, Douxie, Nari, Steve, YN with his heavy armor, and Claire are on the flying ship.

Merlin: We're headed right into the lion's den.

Douxie: You gave me a staff because you trusted me, right? So, trust me.

Merlin: Very well. I stand by your decision wizard.

Douxie: Everyone knows what they need to do. If we pull this off, we'll get Jim back.

They nod before the run into the arcane order ship.

Douxie: Arcane Order! We're here to barter!

They open the gates to allow the team to enter.

Douxie: And that means "come in."

Steve: Wait, we're flying into the bitey devil castle?

They board the ship and heads inside.

Steve: Uh, this is supes dumb. Like, even I know it's dumb, and we're still gonna go inside?

Once they're inside, they wait for the order to arrive.

Douxie: It's quiet, isn't it?

Merlin: Good evening, Skrael.

Skrael and Bellroc arrives as well as the GreenKnight.

Skrael: Surrendering already? I was hoping for a little more cat and mouse.

Bellroc: You will be rewarded with a quick and painful death.

Merlin: A fight here will end poorly for all of us. We seek a truce. Go on, Hisirdoux.

Douxie: Good evening, doers of evil and ancient terrors. We have a proposal: a trade. One of yours for one of ours.

Bellroc: Our missing third in exchange for your Troll mongrel?

Skrael: You would give up your only advantage? What does this gain you?

Douxie: Yes, well, an excellent question, one that requires a long, thoughtful, time-consuming answer.

Douxie explains a long story about the reason which took a few minutes.

Douxie: And, finally, my friends and I returned back to the present. [chuckles] My, what a journey, eh, Nari?

Nari sneezes which got the order curious. 

Skrael: Nari, are you unwell?

Douxie: Uh, no, no, no, no, no. Nari's just a bit jet-lagged is all! It's a human phrase for, you know, traveling in jets and lagging a little. Pull it together, Nari.

Steve stays hidden from them while they're waiting for the other team.

Steve: Jeez, what's taking them so long? I would have gotten Lake out by now!

Unbeknowns to them, Claire and YN sneak their way in the ship to find ship thanks to Claire's teleportation.

YN: Claire, should this fail...

Claire: It won't-

YN: If it fail, don't hesitate to pull everyone off of this ship.

Claire nods before YN stomp his feet to use his seismic senses to find Jim. Once he detected him, they head there to find Jim sitting at the corner.

Claire: Come on, let's go. We're getting you out of here.

Jim growls at his friends. YN got his chains ready but Claire stops him and he nods yet stays in guard as Claire tries to talk to Jim after creating a portal.

Claire: Easy. Easy. This isn't you. You're James Lake, Jr. The Trollhunter.

Jim: Jim is gone. The Knight freed me.

Douxie: Nari's fine. Simple explanation. Right, Nari?

Nari: Oh, right.

Suddenly Nari turns back into Archie before he barfs hairball.

Archie: I guess the "me" is out of the bag.
(Nervous chuckles.)

Douxie: Oh, fuzz buckets.

Bellroc: You dare deceive us?

Archie: Well, in all fairness, I wasn't expecting a rogue hairball.

Skrael: Where is Nari? The real one!

The real Nari stayed behind at the hex tech with the rest of the team.

Bellroc: This castle shall be your tomb!

Bellroc blast fire at them, but Merlin uses his magic shield against it.

Merlin: Your ruse has failed! We must go now, to protect Nari!

Douxie: We're not leaving without the others and Jim!

Merlin: Yes, we are!

Merlin takes down the arcane order but the green knight knocks the wizards back. Leaving Steve alone.

Steve: Oh, dang! Do I dive in to save the day, or do I go back to the ship? Can I fly it? Will Wizard-Dad get mad if I do? Ah, dang! Palchuk Charge!

Steve holds out his Axe and charges at them.

Skrael: (Sighs.) Annoying mortal.

Skrael freezes the ground and Steve slipped and slides away. Back with Claire and YN, they still try to save Jim from the order. 

Claire: Please. You said we'd always find a way to save each other. I love you. We belong together.

Jim: (Growls.) I...belong...here!

Jim attacks Claire as she avades his attacks.

Claire: Jim! Come on!

Jim goes for the attack again but this time YN uses his chains to hold him from hurting Claire.

YN: You're not making this easy for us, are you?

Claire: We'll help you.

Claire uses her magic to teleport Jim away from underneath, but it was then disappeared.

???: The boy is gone, little lambs.

They see Morgana floating down and they were surprised to see her return to this world.

Claire&YN: Morgana!?

YN: I thought we banished you to the shadow realm!

Claire: You just won't die, will you?

Morgana: The Order had other plans. There's no way out, I'm afraid, for any of us.

Morgana attacks Claire and YN as Jim charges at them. But Claire and YN saw it and YN uses his earthbending to knock Morgana away and holds Jim as they both try to overpower each other.

YN: Run, Claire! I'll hold them off!

Claire: I won't give up on you, Jim. I'll find a way.

Claire uses her teleportation and escape while YN still holds Jim until he headbutts Jim and swings a punch to knock Jim out cold. YN catches his breath and before he could take Jim, he was blasted by Morgana's magic. He gets back up before Jim grabs him and throws him to the window. It only takes one blast of Morgana's magic to knock him out of the window and he falls. Back with the others, they weren't doing well against the order.

Bellroc: Foolish servant! You think you can stop us? We planned for a millennium, gathering, waiting-

She kept getting interrupted by Skrael playing with Steve who's keep slipping on the ice until he does a split which made him laugh.

Bellroc: Do you mind?

Skrael: Sorry, it's just so fun.

Bellroc: -to undo you, to undo all!

Douxie uses his magic against the GreenKnight, but it didn't work against the knight for some reason. 

GreenKnight: Your magicks are nothing!

The knight knocks him away before Merlin jumps in to protect Douxie and Archie

Merlin: Stay away from him!

Merlin uses his magic to levitate the rocks and throws it at the knight before helping up his apprentices.

???: You don't recognize me, old friend?

The knight gets back up and removes his helmet which caused the wizard to gasps to see what they never expected to see. King Arthur himself.

Merlin: Arthur! My king...How? Why?

Arthur: After I fell in battle, there was darkness. But they made me anew.

Merlin: No! It cannot be!

Jim then arrives and grabs Douxie and Archie while Skrael freezes Steve and Claire who just arrived.

Bellroc: We propose new terms.

Skrael: Give us Nari, or he dies.

Merlin: Hisirdoux!

Douxie: I'm sorry! This is my fault!

Merlin: (To Arthur.) I know not what darkness twists you, but you will not harm the boy! Not while I draw breath!

Merlin unleash his magic to stop the order and does his best to stop Arthur. But he was too fast as he grabs Merlin's throat and pins him to the window.

Arthur uses his sword to stab the wizard to the chest and he screams.

Douxie: No!

Merlin: My friend...what have you become?

Arthur: Our redemption.

Morgana: (Arrives.) It's over.

Arthur toss Merlin to the window and let him fall down.

Douxie: No!

Douxie unleashed his magic to free himself and his friends as well as knocking the order away.

Douxie: Get out of here!

Claire, Archie, and Steve escape through the portal while Douxie fly's straight down to save his mentor as fast as he can until he successfully caught up and landed in the nick of time.

Douxie: Hang on. Hang on, Master. Hang on!

The others arrive and were shock to see Merlin is dying.

Archie: Oh, no!

Claire: Douxie!

Steve: He looks bad.

Douxie: Hold still. I can fix this! (Hesitates and uses his magic.) I can fix this! I can-

Merlin: (Calm.) Stop, Hisirdoux. No one can. Do not blame yourself.

Douxie: I'm sorry. I should have listened to-

Merlin: No, no. I'm sorry. I spent a lifetime serving the wrong master, trying to save this world.

Douxie: (Sobs.) You can't! You're Merlin, the greatest wizard of all time!

Merlin: I saw a glimmer of greatness of what you could become. And the greatest thing I have ever accomplished was saving you.

Douxie: (Sobs.) I'll try and make you proud.

Merlin: You already have...son.

With his last breath, the wizard leaves the world of the living.

Douxie: No. No, you can't go! No, please. I'm not ready.

Merlin then turn into ash and vanished. Only to leave a book behind.

Claire: Douxie, I'm so sorry.

Archie: I... I can't believe he's gone.

Soon they hear someone coming and it reveal to be YN.

Claire: You fell? How did you survived?

YN: Hard landing. Plus the armor protected me from my fall. Also, I found this.

YN holds out Merlin's staff when it fell. Douxie picks up the book that's left behind.

Steve: What is that?

It's all we have left to guide us. Other than that we're on our own.

YN: So be it.

Without Merlin, all they can do now is use the book that Merlin left behind. Otherwise, what other hope do they have to save the world?