Yugo was teleported away by Yuzu's bracelet when she reunited with Yuya. Teleported to Academia in the middle of a classroom, Yugo rides off. Meanwhile, Serena contacts Leo Akaba and tells him she has Yuzu; with this, all four girls Leo needs are his. He sees Yusho arrive on the island via surveillance and tells his image it is time to learn the truth. At the docks, Yusho, Asuka and Kaito arrive to find now a single soldier. Yugo finds them and Asuka tells him about Rin, and he and Kaito run off separately to find Rin and Ruri. Yusho and Asuka decide to confront Leo. Yugo and Kaito arrive at the Tower of the Sun and Tower of the Moon, respectively. Awaiting them are the tower guardians, Apollo and Diana. To enter the tower they must duel.
Dianna takes the first move against Kaito and Fusion Summons "Moon Protector" and uses its effect to Special Summon a "Protector's Shield Token." As long as the token remains in play, Moon Protector cannot be attacked. Diana sets a card and ends her turn. Kaito Xyz Summons "Galaxy-Eyes Cipher Dragon." In response, Diana activates her trap "Protector's Adoration." Since her opponent controls a monster summoned from the Extra Deck, its effect is negated and Diana summons two more Protector's Shield Tokens. Galaxy-Eyes can now attack all her tokens this turn, but if it does not it will be destroyed. Kaito attacks a Shield Token and destroys it. Since a Shield Token was destroyed, the effect of Moon Protector activates. Galaxy-Eyes loses 800 ATK, and Diana gains 800 Life Points. Faced with Galaxy-Eyes being destroyed if he doesn't, Kaito attacks the other two tokens. Diana rises to 6400 Life Points while Galaxy-Eyes has only 600 ATK left.
Kaito activates "Rank-Up Magic Cipher Pursuit" from his hand since the difference between their Life Points is more than 2000. He ranks up Galaxy-Eyes into "Neo Galaxy-Eyes Photon Dragon." Cipher Pursuit lets Kaito activate its effect immediately and he does so, detaching all Xyz Materials from it to take control of all of Diana's monsters and treat their names as Neo Galaxy-Eyes'. He further activates "Galaxy Nova" and tributes Diana treated as a Galaxy-Eyes monster to revive Galaxy-Eyes Cipher Dragon. Kaito's dragons attack directly and Diana is defeated.
In Yugo's duel with Apollo, he goes first and Fusion Summons "Sun Protector" and with it a Protector's Shield Token to defend it from attacks. Apollo sets a card and ends his turn. Yugo swiftly Synchro Summons "Clear-Wing Synchro Dragon" and Apollo activates Protector's Adoration, negating Clear-Wing's effect and summoning two more Shield Tokens. Clear-Wing attacks a Shield Token and its destruction activates Sun Protector's effect, dealing 800 damage to Yugo and decreasing the ATK of Clear-Wing by 800. Yugo attacks the remaining tokens, falling to 1600 Life Points while Clear-Wing is at 100 ATK.
Since Yugo took damage during his Battle Phase, he Special Summons "Speedroid OMK Gum" from his hand and uses its effect to instantly perform a Synchro Summon. He tunes Clear-Wing and OMK Gum to summon "Crystal-Wing Synchro Dragon." The effect of OMK Gum activates since it was sent to the Graveyard for a Synchro Summon, and lets Yugo draw a card and reveal it; if it is a Speedroid monster, Yugo's Synchro Summoned monster gains ATK equal to that monster's. Yugo reveals "Speedroid Ohajikid," boosting Crystal Wing to 4000 ATK. Crystal Wing attacks Sun Protect, its effect increasing its ATK by the ATK of Sun Protect. Apollo is defeated.
Kaito and Yugo enter the two towers and find Ruri and Rin. Rin embraces Yugo, but suddenly grins behind him. Watching the surveillance feed, the Doctor, Leo's aide, holds up a card, "Parasite Fusioner." In Rin's room, the same monster on the card is shown in the corner of the room.
This episode contains the following tropes:
- Antagonist Title: The episode refers to the Keepers of the Towers who are named after Diana and Apollo.
- The Bad Guy Wins: With the four bracelet girls are now under the Professor's possession, all he's got to say is:The Professor: Now, all the pieces have been assembled. Yusho Sakaki, it seems like the time has finally come to reveal everything to you.
- Curb-Stomp Battle: The two tower guardians get taken out in very short order by Yugo and Kaito.
- A physical version occurs earlier in the episode, when Yugo tries to jump Kaito and gets pinned to the floor literally one second later.
- Dope Slap: The moment when Rin is about to be glomped by Yugo, who is getting too touchy-feely for her taste, she knees him in the stomach.
- Freeze-Frame Bonus: Ryo Marufuji's name can be seen on the blackboard, written in English, in the classroom Yugo was teleported to.
- Insistent Terminology:Academia lecturer: Hey! No bikes in the hallway!Yugo: It's not a bike, it's a D-Wheel!
- Mythology Gag: Several.
- Guess where Kaito's last on-screen Duel takes place in ZEXAL.
- His summoning of Neo Galaxy-Eyes Cipher Dragon and Galaxy-Eyes Cipher Dragon mirrors the climax of his second duel with Yuma in ZEXAL.
- Yugo's opponent in this episode is based on The Supremacy Sun, one of the ten Legendary Planet monsters used by Tragoedia in the GX manga.
- Antagonists using monsters with the Sun and Moon theme with one facing a D-Wheeler echoes Rex Godwin's two Synchro Monsters before he ditches them for his Earthbound Immortal. Having a Plot Device involving towers is another nod to 5Ds where the Signers had to deactivate the towers the Dark Signers were guarding to prevent the King of the Underworld from being unleashed to the world.
- Yugo has been shown with Yusei's old card Urgent Tuning in his hand and it does feature Junk Warrior in its artwork but Yugo never uses it as he Synchro Summons during the Battle Phase via monster effects. His new Speedroid OMK Gum also has an appearance similar to Rua's Morphtronic monsters, complete with transformation sequence.
- No Kill Like Over Kill: Compared to Yugo, Kaito ended his duel against the moon guardian by summoning both of his Galaxy-Eyes after wiping her field and having them both attack at once.
- Oh, Crap!: Both of the guardians when they're about to be finished off, but Diana in particular is practically on the verge of soiling herself. Especially given that Kaito takes his sweet time ordering his Cipher Dragons to attack and dropping his Catchphrase to hammer in just how screwed she is.
- Revealing Hug: Textbook example with Yugo and Rin sharing a reunion embrace only for the latter to flash a sinister grin right before the credits.
- Skewed Priorities: You'd think that the lecturer would be more concerned about the fact that Yugo materialized on top of his desk out of nowhere and crashed through a wall than the fact that he's riding a bike in the hallway...
- Slasher Smile: Holy crap... Rin, that creepy grin of yours!
- Tsundere: RIN. She greets Yugo by repeatedly kneeing him in the gut, then cries about how stupid he is for being late to rescue her, and hugs him.
- Wham Episode: The first one since Episode 98. The four bracelet girls are now assembled as the Professor expected, and the Arc Area Project is about to begin shortly.