After departing from Jack Sparrow and the others, the group left with Sora, Donald and Goofy back out into the universal highway.
"So, where do you guys think we should go now?" Theo asked.
"Not sure, and with Simon being MIA who knows where he could've wounded up." Ace said.
"I'm sure he's fine, Ace. Cmon, he's an Umbra Warlock. Don't you have faith your brother's okay?" Hope asked.
"I do, don't tell me none of you don't tend to worry about your siblings too." Ace said.
"All the time. Even Jack." Hope said. "You worry for Harumi sometimes, David?
"Very much. But I know she's in good hands." David said.
"I never had to worry for my brothers because they're a lot stronger than me." Jexi said. "But if something ever does happen, I will come running every time."
"You just need to have a little…." Sora said before his gummiphone started ringing. "Uh...I better take that." he said pulling his phone out and answering. "Hello?"
"Sora! It's horrible! Terrible!" Dale said.
"Whoa, Dale, slow down! What's going on?" Hope asked.
Chip ripped Dale from the screen and piped in. "It's the King, Riku, Bartolomeo and Cavendish! They're in the realm of darkness, and we've lost contact with them!"
"In short….they gotta be in trouble!" Dale shouted.
"That's bad news." Hope said. "And we can't even get to them the normal way because we closed the Door to Darkness after we beat Ansem."
"And without Simon, no portal to there either." Ace added.
"Let your heart...be your guiding key." Sora said as he pointed his Keyblade out as a portal opened in the ship's path.
"A portal!" Goofy said.
"But to where?" Sora asked.
"Doesn't matter! Just go!" Donald said.
The Galaxy King raced through the Gate as they traveled all the way… to Destiny Islands.
"What the? The Destiny Islands? Why did it take us here?" Pit asked.
"Wait...I think I saw something...shining in the sands." Ace said.
"Touch down. We need a closer look." Hope said.
As soon as the ship landed, the group exited as they saw a keyblade lying in the sands.
"Wait...I know this blade. It's Master Eraqus's!" Aqua said in shock.
"So this is where it ended up." Hope said. "But why is it here?"
"Could it…" Aqua said as she picked it up. She pointed it to the island as a ray of light shined out and made a door appear over the entrance to the hidden place.
"Do you think that leads to…" Jesse started.
"The Realm of Darkness? I couldn't think of a reason why it wouldn't." Theo said.
"Aqua, lend the Master's Defender to Sora for a moment." Ace said.
"Guys...I'm sorry to have to do this….Barrier!" she said as a barrier separated them from her.
"Aqua? What're you doing?" Hope asked.
"Hope...you and I have shared a lot of memories together...all of you have. But I can feel it. The other me in there...her heart screaming for help. I'm sorry...but for now...I need to go in alone." Aqua said.
"You don't need to apologize. We all need to face our darkness someday. Sectonia conquered hers alone. It should be the same with you, right Sectonia?" Hope asked.
"That's right. I know better than anyone, this is something she has to do on her own." Sectonia said.
"And don't worry. I'll make it back out. With all of them by my side. I won't end up lost." Aqua smiled as the door opened for her as she went inside.
In the Realm of Darkness…
Riku, Mickey, Bartolomeo and Cavendish were battling against a Demon Tower that was beating them at every turn.
"Riku, Look out!" Mickey called as the Demon Tower knocked him down before capturing him.
"Mickey!" Riku shouted.
"Not good. We're surrounded on all sides." Bartolomeo said.
"Seems we're not going to be able to make a clean escape from this." Cavendish said.
"Uh… what's going on with the heartless?" Bartolomeo asked as a humanoid figure emerged from the tower and landed on the ground, collecting Mickey's keyblade.
"This Keyblade." the figure said in a familiar voice.
"That voice...can it?" Mickey groaned as the figure was revealed to be the other Aqua, now turned to darkness.
"Mickey...you're too late." she said.
"Aqua?" Cavendish asked.
"No, it's the other one. The One hoopa summoned with us." Bartolomeo said crying. "Our Aqua-senpai!"
"Save it, traitors." She said to them. "You know as well as I do that Hoopa didn't intend to keep us at his side. So… he tossed us into this realm. And you abandoned me."
"We didn't abandon you. We got summoned by some poser umbra witch guy...whatever that is. I still don't understand it." Bartolomeo said.
"But...what happened to you? You did not look like this when we got pulled away." Cavendish said.
"Loneliness...the feeling of being alone...I was left here for far too long with no one to be with...this is all the fault of Hoopa...and Mickey." Aqua said.
"I know. I'm sorry." Mickey said.
"I reached this shore after endless wandering. Waited forever for help to arrive. But no one came." Aqua said. "I lost my keyblade. Had no way of fighting against the endless hordes of heartless. You all should've known I was stranded. Do you have any idea how lonely it is here? How it feels to have no one? All that's left in my heart is misery and despair… and now, I'm aiming to share it with all of you!"
"Aqua…" Cavendish said.
"Aqua-senpai…" Bartolomeo said before the two looked at each other before blocking off Riku.
"If you want them, you'll have to go through us first." Cavendish said.
"We're sorry we left you behind...but no matter what…" Bartolomeo said.
"We're going to make sure you come back with us!" both said at once.
"You'll have to get past this first." Aqua said as the Demon Tower resurfaced.
"Damn it…." both said before something jumped by their side. "Huh?"
"So...there was someone else with you two...I didn't realize." the voice said as Simon stood up.
"You? But...what are…" Cavendish said.
"Save it, you guys could use some help, and Bartolomeo." Simon said. "Watch what you say next time."
"Don't go talking to me like you're my senpai." Bartolomeo said.
"We can settle this later. Mickey is inside that tower." Cavendish said.
"That's right...he needs us all." Riku said joining them.
"But...can the four of us really take down that mass?" Bartolomeo asked.
"What this Aqua said, about her sharing the misery and despair she amassed? There's no need for that." Riku said. "We got our own." he said as his dark self appeared by him.
"Yeah… I have Hakuba to contend with every day." Cavendish said.
"And I was a mob boss." Bartolomeo said.
"I've lost my parents to the Titans, so it's just me and my brothers, so we have to look out for each other from now on." Simon said.
"Let's kick this tower's ass!" Bartolomeo said as the four assumed their fighting poses. But just as they were about to fight, a door opened in the sky as descending from it was the current Aqua.
"What?" Anti-Aqua asked.
"I made it…" Aqua breathed.
"Aqua… OUR Aqua." Riku smiled.
"Whoa….it's like looking in a mirror...a twisted one." Simon said.
"You…" Anti-Aqua growled. "You took away my life."
"I didn't. All I did was escape the darkness with a friend. You just fell for Hoopa's tricks." Aqua said.
"The same thing would've happened to you, after all, you're me. I've waited for so long, but nobody came, and now that you're here...I will do what I should've done a long time ago!" Anti-Aqua said as she got into a fighting stance with Mickey's keyblade.
"You four save the King. I have to Save myself." Aqua said.
"Alright, be careful." Simon said as the four charged at the Demon Tower.
(Cue- Anti-Aqua- Kingdom Hearts 3)
"Feel the pain that I've endured for 10 years!" Anti-Aqua said as she activated Spellweaver and warped.
"I won't fall the same way you did." Aqua said activating Ghost Drive as she warped as well, the two entering a clash against one another as large sparks surged each time their keyblades clashed with one another.
"Go!" Anti-Aqua called as she and two clones fired three magic spheres before disappearing again.
"She's warping all over the place. In which case…" Aqua said.
"Oh man this is getting intense." Bartolomeo said as the four watched after having taken down the Demon Tower.
"They're both so...equally matched." Riku said.
"Hello? Hel...lo?" a staticy voice said on the comm.
"Wait...is that...Ro?" Simon asked while getting blank looks. "I'll explain later. Ro, it's Simon, are you there?"
"Yes. The signals' weak but we can still communicate. Look...this may be a long shot...but there may be a way to resolve the paradox that was created." Ro said.
"What do you have in mind?" Simon asked.
"This started cause of Hoopa and Hope messing with their Aquas, one having been trapped and the other being in the light. I think that a collaboration should…" Ro started.
"Look not all of us are rocket scientists so give us the simple version." Simon said.
"You need to have them touch physically. That should merge the timelines back into one, resolving the paradox." Ro said.
"But how do we do that? I mean one of my Infernal Demons could help, but which one?" Simon asked.
"Wait...we don't need any Infernal Demons." Bartolomeo said. "Aqua-senpai! Use Bind on the other one!"
"Okay. Bind!" Aqua said binding her anti opposite.
"Now...Barrier Ball!" Bartolomeo said entrapping the two of them in a large sphere.
"No!" Anti Aqua said trying to break out.
"Nothing can break my barriers. Not only that, but I can control their size." Bartolomeo said as the sphere started to shrink.
"What? Let me out! You all must pay!" Anti Aqua said.
"Aqua...you know...we can't live apart...we need to be...together." Aqua said grabbing Anti Aqua's hand as a bright light shined within the sphere.
"Whoa!" Riku said.
The light faded, there inside was only one Aqua as the sphere vanished as she fell onto the coast.
"It worked." Simon said.
It wasn't until later back on the Destiny Islands that Aqua began to awake being surrounded by everyone. "Where am I? In...the realm of Darkness?" Aqua asked.
"Nope. Back among the living. And in one piece, if I may add." Jesse said.
"I'm so glad… you're back." Hope sobbed.
"It seems my theory was right on the money. No more paradoxes...only one single Aqua." Ro said.
"That's right. Me and her...we joined together." Aqua said.
"This is so heartwarming." Hagakure said.
"It's gonna feel even more amazing when we bring Terra and Ven back." Rainbow said.
"Speaking of...we have everything we need now right?" Hope asked.
"With Master's Keyblade back in my possession...we can finally wake Ven." Aqua said.
"So...where do we go then?" Dan asked.
"Castle Oblivion." Hope said.