Yuma is sleeping in his room while Astral is inside the Different Dimension Airship within the Emperor's Key, musing that he has collected fifty "Number" cards and is determined to find the other fifty. The pillars glow and Astral is surrounded in a blue Sphere Field as he recalls the memories. In the Barian World, Mizar approaches Dumon and comments on the fact that Girag and Alito were still not able to produce good results. Dumon decides to send Mizar to Earth saying that he is the only one who can do it now. Mizar responds that his is how he thought it would go to begin with. Before Mizar leaves, Dumon hands over three cubes known as Barian's Sphere Cubes, which will let Barians use their original powers even in the human world. That way, they won't have to brainwash humans, they can take the "Numbers" themselves instead, though he clarifies that the the generation of the Sphere Field is only temporary and explains that he didn't previously think they would need them. Dumon tells him to give one cube to Girag and one to Alito, calling this their "last chance". As Mizar leaves for Earth, Dumon puts full trust in him, hoping he will produce better results than the other two.
Mizar vanishes through a portal and reappears in a realm where he confronts a dragon emerging from a cave. He pulls out a blank card and starts absorbing the monster into it. He is pushed back as the dragon roars and chunks rock fly about, but he is eventually successful, the dragon becoming streams of pink energy which surge into the card. He comments that that exhausted him as usual. Yuma runs on a path with Astral and trips. Suddenly, an unknown dragon comes and attacks Astral. Yuma and Astral confront this terrifying-looking dragon. As Yuma calls out for Astral, the concrete path breaks apart and Yuma falls through the resulting gap. Yuma wakes up, realizing it was a dream. Still, he is anxious Yuma, wondering if he can really protect Astral in his current state During the early morning, Girag and Alito are in a forest doing extensive training, doing all sorts of exercises while "drawing". Girag claims he is Setting a bear face-down after punching one out. Girag falls in the end and is tired. Alito calls him pathetic, with Girag responding that Alito should be grateful they are training together.
Suddenly, the sky turns gray and a lightning bolt strikes, with a red energy ball appearing. Girag and Alito recognize it as something from the Barian World and decide to check it out. They arrive there to see a large crater, with Girag saying that there is no mistaking the power that created it - Mizar has come. Sometime later, Mizar hands over the Sphere Cubes. Girag and Alito are both pleased, both thinking they can defeat Yuma now. Until now, they'd been force to brainwash incompetent humans. Mizar tells them they train as hard as they like and quickly departs, perturbing Alito in the process. On the way back home, Rei asks Tori what's wrong with Yuma. Tori responds that she doesn't know, but he's been like this all day, commenting that she's not seen Astral either. At Yuma's house, his family eats dinner, with Kari saying their grandmother's roast meat and potatoes are the best. Haru says they are both free to have more, but Yuma's not finished what he has already and says he's finished and doesn't have much appetite, shocking Kari and Haru. Inside Yuma's room, Yuma looks over at his Deck to figure out a way to counterattack the Barians' "CXyz" monsters and thinks that if he doesn't think of something soon enough, then he won't be able to protect Astral. Meanwhile, Astral is still gathering his memories inside the Key.
Just as Tori is getting out of the shower, she receives a call from Haru, who asks her to go to the Duel Sanctuary with Yuma the next day when they have off for a school holdiay, thinking the fresh mountain air would help him. Tori asks why she was asked to go and Haru doesn't have a clear answer, which seems to make Tori nervous and she almost drops her towel. The next day, Tori accompanies Yuma to the Duel Sanctuary. There they meet Kaze again, only to find out that Roku is not here at the moment. They've also brought them more supplies and Yuma seems annoyed that Roku isn't there. Regardless, Kaze welcomes them and lets him stay for the night. Yuma stays in the room with the Wooden Duel monsters. Yuma stumbles upon the "Red-Eyes Black Dragon" statue and is reminded of his nightmare involving the mysterious dragon, worrying Tori. Kaze comes in and says Yuma sees frusturated. Counseling him, he says he used to be the same way He then gives Yuma two cards, "Overlay Chain" and "Overlay Bullet". Kaze states that Roku gave those cards to him to pass on to Yuma. Yuma is surprised that Roku knew he would fell this way and Kaze responds that their "master" can easily see through his disciples' hearts. Yuma believes that these two cards can be used in an attempt against the Barians and will treasure them properly.
The next day, Tori and Yuma visit the river bank. Yuma sits on a rock, thinking about the two cards that Kaze gave him from Roku. In an attempt to make him feel better, Tori starts splashing Yuma. He eventually comes around and joins her. Meanwhile, in the streets, Rio comes back from the shopping mall, with Shark waiting. Shark tells Rio that she was pretty slow, and Rio, who thought this was a good time to go shopping, suddenly feels the Barians' presence again. This time, she says that "they are going to destroy the most important thing" and "the arrival of the dragon of ill omen". Shark thinks that this has something to do with Barians.
On the way back from the river, Tori is happy that Yuma is feeling much better and Yuma thinks that all of that was to make him feel better but Tori denies it while blushing. She tells Yuma that they need to go back to the Duel Sanctuary quickly or else they might catch a cold. At that instant, an energy ball knocks Tori down. It is revealed to be Mizar, calling out to Yuma. Mizar immediately throws his Barian Sphere Cube and expands it, surrounding Yuma in a red Sphere Field. The Sphere Field then expands into a giant energy ball. Inside the Emperor’s Key, Astral, who is still absorbing his memories, suddenly feels the power and wonder what it is. Mizar comes in and introduces himself as Yuma’s last Dueling opponent. In Kite's laboratory, Orbital 7 has claimed that a powerful energy source was detected in area 753 and speculates that it is similar in power to the Sphere Field. Kite thinks that it has something to do with the Barians. Yuma, inside the Sphere Field, correctly deduces that Mizar as a Barian. Mizar asks if he is scared, but Yuma denies it. Mizar asks Yuma if he will accept the Duel and Yuma answers back, "of course". The two arm their D-Pads and D-Gazers.
Yuma begins his turn, with Astral appearing and asking Yuma what's going on. Mizar is glad to see Astral finally come out. Astral is surprised Mizar can see him and Yuma tells him he's a Barian and that Astral shouldn't worry. Yuma Normal Summons "Goblindbergh", whose effectactivates, letting him Special Summon a Level 4 or lower monster from his hand. He Special Summons "Ganbara Knight", who bursts from the box carried by the three "Goblindberghs". Yuma overlays his two Level 4 monsters to Xyz Summon "Number 39: Utopia" in Attack Position. Yuma examines his hand, which contains "Dododo Warrior", "Gagaga Girl", "Overlay Bullet" and "Overlay Chain". He's pleased to have both "Overlay Chain" and "Overlay Bullet", but thinks he must win for Astral's sake and knows the opponent will use a "CXyz". He equips "Utopia" with "Overlay Chain", which protects its Overlay Units from the effects his opponent uses. Astral sees what Yuma's doing - even if the opponent uses "Rank-Up-Magic Barian's Force", the Overlay Units of "Utopia" are protected. However, he's shocked he chose to use a defensive card like "Overlay Chain" instead of "Overlay Bullet", which would have detached the Overlay Units to inflict 500 damage per Unit detached. Yuma says he must be extra-cautious here and Astral compliments the tactic.