- Story Arc: The Avalon Clan; The Archmage's rise and fall
- Characters: Goliath, Elisa, Bronx, the Avalon Clan, Tom, Mary, the Magus, Katharine, Constantine, Finella, the Archmage, Demona, Macbeth, the Weird Sisters, King Arthur
- Enemy(ies) : Constantine, the Archmage, the Weird Sisters
Tom, now a middle-aged man, visits Manhattan in search of Goliath to take him, Bronx, and Elisa to Avalon. He tells them about his journey with Katharine, the Magus, and the Eggs from Castle Wyvern to Edinburgh, the murder of King Kenneth by the usurper Constantine, and their subsequent escape to Avalon.
On Avalon, Goliath is introduced to the Avalon Clan: the Eggs from Castle Wyvern grown to adolescence. The Archmage taunts them with a spell to animate the sand, which Goliath defeats. While the Avalon Clan defends their castle against attacks by Demona and Macbeth, the Archmage goes back in time to set his past self on the course to become his future self. Elisa decides to awaken the "Sleeping King" in the Hollow Hill, who is none other than Arthur Pendragon; with his help, the Avalon Clan defeats Macbeth and Demona; the Magus defeats the Weird Sisters (albeit at mortal cost to himself); and Goliath defeats the Archmage again, claiming the Eye of Odin and the Phoenix Gate to ensure that they are never used again.
After the battle is won, Goliath, Elisa, and Bronx depart from Avalon, and Angela decides to accompany them.
A facsimile of Demona next appears in Shadows of the Past. Macbeth next appears in Sanctuary. King Arthur next appears in Pendragon. Tom, Katharine, and The Weird Sisters next appear in Ill Met By Moonlight. Mary, Finella, and Constantine next appear in The Gate.
This Episode contains the following Tropes:
- Achilles' Heel: The heroes' plan is to take the Eye of Odin from the Archmage. They think it will just make him less powerful. What they don't know is that he can't control the Grimorum's power without it.
- Affectionate Nickname: Tom, Katherine, and Magus call the Avalon gargoyles "the eggs" even after they are fully grown.
- Brainwashed and Crazy: Played with. Macbeth and Demona are being compelled to act against their interests, but their personalities are largely the same. Both of them hesitate at hurting innocent/young gargoyles, until the Archmage doubles his brainwashing efforts. More specifically:
- Macbeth recognizes King Arthur's name and expresses his enthusiasm for fighting a legend.
- Demona's arrogance and hatred for humans slips through and she stops her assault on the Avalon Clan when Elisa appears, focusing her efforts on her.
- Brought Down to Badass: At the height of his youth and with the Grimorum in his hands, Magus easily defeats the Weird Sisters. As an old man with nothing but a walking staff, he can still defeat them, but at much greater effort, cunning and sacrifice.
- Brought Down to Normal: The Magus, without the Grimorum, is no different than any other old man. Part 3 shows he can still cast spells, but only by siphoning magic from Avalon. Even then, without a magical artifact, he has to channel the magic through his own body directly. It ultimately kills him.
- Chekhov's Gun: The Animated Armor that guard King Arthur in part 2 are the key to defeating the Weird Sisters in part 3.
- Cold Iron: Similar to what happened to Puck, Magus restrains the Weird Sisters with chains made from iron armor. This forces them to come to terms with Goliath in the battle's conclusion.
- Continuity Nod: "A Lighthouse in the Sea of Time" involved an attempt by Macbeth to acquire the scrolls of Merlin, in which at one point Macbeth gave an impassioned monologue regarding Arthur. Now, King Arthur himself appears, alluded to in part 2 as "the sleeping king" and awakens in part 3.
- Deadpan Snarker: The Archmage gets a number of stinging lines at his past self such as "If you don't know, then don't guess" and "try to show some dignity, will you?"
- Extreme Omnivore: Thanks to the power given to him by the Eye of Odin, the Archmage was able to devour the Grimorium.
- Field Power Bonus: Magus can use magic in Avalon because of its high concentration of magical energy. However, the Weird Sisters are aided by it even more.Weird Sisters: AVALON! AID YOUR CHILDREN!
- Foreshadowing: Part 2 casually mentions "the Sleeping King" being on the island. Part 3 sees him woken up.
- Genre Blindness: The Archmage's younger self is constantly slow on the draw, much to the annoyance of his older self."If you don't know, don't guess!"
- Heroic Sacrifice: Magus confronts the Weird Sisters knowing that it will definitely kill him, either through their efforts or his own.
- Hopeless Suitor: The Magus explains to Eliza that he's been in love with Katharine for decades of Avalon time, since before Hackon's attack, but always felt unworthy of her. Because of this, he said nothing and she never noticed.
- How We Got Here: Part 1 is mostly Tom explaining how he, Katherine, Magus and the eggs traveled from Castle Wyvern to Avalon.
- I Hate Past Me: The Archmage visibly shows annoyance at his younger self's ignorance, and voices his delight when the two finally part.Archmage: Finally! I thought he'd never leave.
- "I Know You're in There Somewhere" Fight: Goliath appeals to Demona and Macbeth's better natures to try to snap them out of the Archmage's control. It only works briefly.
- It's Personal: The Weird Sisters want payback against the Magus for their earlier encounter, but it becomes even more personal in Part 3 when he uses the magic of Avalon to hurt them."You steal magic from the land of our birth. You will suffer!"
- Killed Off for Real: Magus suffers a fatal case of Cast from Hit Points and the Archmage dissolves from Power Degeneration.
- Loophole Abuse:
- When the Archmage tells the Weird Sisters to watch over and guide Demona and Macbeth, the Weird Sisters say Oberon forbid them from directly interfering with mortals. The Archmage notes that the rule that cannot be broken can be bent, so they indirectly interfere by goading the two into making an alliance with each other.
- Oberon's law dictates that no foreign magic can be brought onto Avalon. That allows for the Eye of Odin and the Phoenix Gate, but not the Grimorum. The Archmage gets around this by swallowing it and making it a part of himself.
- My Future Self and Me: The Archmage spends most of Part 2 interacting with his past self to get him ready for the Battle of Avalon.
- Place of Power: Avalon is more magical than elsewhere in the world and the Hallowed Hill is especially magical. This enables Magus to cast spells without the Grimorum by drawing from it.
- Rhetorical Question Blunder: This exchange when the younger Archmage learns that the Grimorum isn't allowed on Avalon.
- Royals Who Actually Do Something: After the attack on Castle Wyvern, Princess Katherine devotes herself to the care of the gargoyle eggs, basically becoming their foster mother. She also protects them during the battle.
- Sentient Sands: With his immense magical power, the Archmage was able to attack the group through the sand of the island's beach.
- Stable Time Loop: The Archmage obtains the relics and knowledge because of his older self traveling through time and showing him what to do.Archmage: Are you sure you know what to do?
Other Archmage: I should. I watched you do it.
- Take Over the World: When the Archmage's younger self admits he hadn't thought about what he'd do with the ultimate power he desired, he considers using it to conquer Scotland. The Archmage advises him to think bigger, as he'd have enough power to rule the entire planet.
- Took a Level in Badass: The power of the three relics has increased the Archmage's magic and even his physical body.
- Wham Line:Tom: I thought you understood, Elisa! Avalon doesn't send you where you want to go, Avalon sends you where you need to be!
Elisa: Wait, what does he mean "where we need to be"?
- Whole Episode Flashback: The first part shows how Tom and the group got to Avalon. The second part shows how the Archmage survived and obtained the relics. Not so much a flashback with the latter, but the Archmage going back in time (see Stable Time Loop).
- Why Don't You Just Shoot Him?: During their fight, the Archmage boasts he could simply kill Goliath with just a word.Goliath: Then why don't you?
Archmage: Because I'm having too much fun!
- Wizard Duel: While the others fight with mundane weapons such as lasers or maces, Magus and the Weird Sisters fight each other with magic. Agony Beams see plenty of use, the Weird Sisters summon a storm to attack Magus with wind and lightning. He transforms his staff into a tree for defense, and then blindsides them by turning a pair of armors into chains and binding them.
- Year Outside, Hour Inside: The passage of time on Avalon is what allows Tom, Katharine, and Magus to still be alive in the present. The conversion rate is one hour inside Avalon is one day outside of it.