Wizard Underground is the eighth episode of Wizards.
The ship arrives back in the present. Steve gets multiple messages on his phone. Meanwhile, the onyx digs deeper into Jim.
Toby, AAARRRGGHH!!!, Blinky, and Merlin are falling and worried about safety. Douxie pulls up beside them and they board the ship. Before they pull away, Nari jumps on board as well.
Shannon makes a wish on some shooting stars that she'll never have to go back to school. The ship crashes into the school and Shannon things she has powers. She wishes for eye lasers, but doesn't get those and is disappointed.
Jim is still hurt and Nari feels that it's getting worse. Merlin reminds Douxie that there's nothing they can do. Just then, the remaining members of the Arcane Order appear and plead with Nari to come back to them. The others protect Nari, even as the Green Knight attacks them. Knowing that he has no other choice and is about to be corrupted anyway, Jim pushes the shard deeper into his own chest to complete the process, making him fully troll. He goes to fight the Green Knight, giving the others time to escape. The Green Knight uses his sword to hurt Jim through the shard and Bellroc tells the Green Knight to take Jim captive.
The Arcane Order flies over Arcadia as Coach Lawrence tells everyone to go home because school's cancelled anyway.
As Douxie promises Claire they'll go back for Jim, Merlin says they can't because they must hide Nari. There's more at stake than they know. Douxie knows a place where they can hide.
Krel goes to a tech store to get replacement parts for the Dadblank. While he's talking to Zoe at the counter, Douxie comes in and talks to her. She leads them into the back. Krel follows them. She leads them into a room, then has to go back to the front of the store. Once she's gone, Merlin has Nari tell them what they're up against. Nari explains what the Arcane Order has done to maintain the balance between magic and mortal. Bellroc and Skrael believe humanity is beyond correction and want to end it all. They're searching for the Genesis Seals. They contain the essence of magic. If they're broken, magic will rise upon the world, wiping it like a flood. All members of the Arcane Order must be present to open the Seals, which is why Nari fled. Merlin has hidden them away, but they still must protect Nari from Bellroc and Skrael. Claire wonders why they need Jim if they're after Nari.
The Green Knight fights Jim, taking his amulet. The amulet was made of the last remaining piece of Morgana and with it, the Arcane Order wants to return her to the world. They say an incantation and Morgana comes out of the the amulet. Morgana is not happy to be back. She says where she was was quiet and peaceful. But Bellroc just tells her to recover her strength because she needs to finish her purpose, to make things right and fix the balance. Morgana says she tried once and lost everything. She begs them to send her back. The Green Knight is the one who convinced them to return her. He takes off his helmet, shocking her. He says they must finish what they began together.
Krel, under Blinky's instructions, is looking for something to help Jim. Merlin tells Claire they can't go back and save Jim. Claire can't just forget about him. Merlin says their priority is keeping Nari safe. Merlin and Claire argue over it, but then Douxie has an idea to save Jim without risking the world. If it works, it'll be quite the magic trick.
Merlin isn't sure about Douxie's plan, but Douxie tells Merlin to trust him. If everyone does what they're supposed to, they'll get Jim back. They approach the Arcane Order and say they want to barter. They're granted entrance. Skrael, Bellroc, and The Green Knight come to fight them. Merlin says they want to make a truce. Douxie explains that they want to trade Nari for Jim. Douxie says it's a long story to explain why that benefits them.
Claire finds Jim.
Douxie finishes telling his time-travel story.
Claire has trouble convincing Jim to leave.
Nari coughs up a hairball, revealing that it's really Archie. The Arcane Order is angry and asks where the real Nari is.
Toby does magic to entertain Nari.
Bellroc attacks Merlin and Douxie. Merlin says they must leave now, without Claire and Jim.
Claire tells Jim she loves him and they belong together. He says he belongs with the Arcane Order. Morgana appears and tells her Jim is gone. They start fighting and Claire says she won't give up on Jim.
Bellroc says they won't give up after planning for 1000 years. They must undo all. The Green Knight attacks Douxie, so Merlin steps in to defend him. The Green Knight then reveals that he's Arthur. A flashback shows the Arcane Order resurrecting Arthur to work for them. Jim jumps down into their area and Claire and Steve are encased in ice. The Arcane Order says they have a new deal: give them Nari or Douxie dies. Merlin chains Bellroc and Skrael, but is unable to chain Arthur, who jumps down and runs a sword through him, killing him. Then he throws Merlin through the window. Douxie is angry and casts very strong magic which breaks Claire and Steve free. He lies down and catches Merlin before he hits the ground. Claire and Steve come through portal. Douxie tries to figure out how to fix Merlin, but Merlin says no one can fix him. Merlin says he spent a lifetime serving the wrong master, trying to save the world. Merlin dies after saying the greatest thing he accomplished was saving Douxie. His body dissolves, leaving behind a book guide them. Aside from that, they're on their own.
- Colin O'Donoghue as Douxie Casperan
- David Bradley as Merlin
- James Faulker as Green Knight
- Kelsey Grammer as Blinky
- Lena Headey as Morgana
- Emile Hirsch as Jim Lake Jr.
- Diego Luna as Krel Tarron
- Lexi Medrano as Claire Nuñez
- Alfred Molina as Archie
- Steven Yeun as Steve Palchuk
- Kay Bess as Bellroc
- Tom Kenny as Dadblank
- Angel Lin as Nari
- Piotr Michael as Bellroc/Skrael
- Sandra Saad as Zoe
- Charlie Saxton as Toby Domzalski
- Fred Tatasciore as AAARRRGGHH!!!
- Bebe Wood as Shannon Longhannon
- Tom Wilson as Coach Lawrence
- It is revealed Zoe is a wizard.
- It is revealed that King Arthur and the Green Knight are one and the same.
- Jim is sadly corrupted by Arthur's onyx shard, becoming a full troll devoid of humanity and Arthur's pawn.
- Morgana is resurrected by Bellroc and Skrael. It is also revealed that she has enjoyed her peaceful life trapped in the Shadow Realm.
- Merlin is killed by King Arthur/the Green Knight.
- When Morgana sees Merlin getting stabbed, she said "it's over". One can argue that it has two different meanings: One being that Merlin's life is over, and the other being her loyalty towards the Arcane Order is over.
- The Amulet of Daylight is destroyed for the third and last time by Bellroc and Skrael to resurrect Morgana.
- There is a discussed theory talked in Aaron Waltke's Twitter page concerning Claire's vision from the Trollhunters episode, "Parental Guidance", about the Amulet of Daylight being destroyed while in the Shadow Realm. In her vision, she sees the amulet being completely broken (including the blue Daylight Stone, which is also the map to Merlin's Tomb). However, when the team finds an ancient gyre and Jim destroys his amulet, the Daylight Stone remains intact. This is implied to be a foreshadowing that the vision not only showed Claire how to find Merlin's Tomb, but that the Arcane Order would destroy the sacred artifact at this very episode to resurrect Morgana.
- Continuity: Merlin is heard saying "I fear it's not a question of where, but rather when", which he says in the first episode. This comes to show that, since they were dealing with time travel and technically speaking, it's like Douxie, Claire, Steve, and Jim were only stuck in the past for just a minute.