Sora felt very out of place in this world given he didn't know much about technology, but that didn't mean he wasn't eager to explore it.

A modern-looking city glowed brightly in the distance and he figured that was where he'd find the keyhole of the world. But how to get there? It was quite a long ways away…

"Maybe with Yakumo I can… jump down there?" Sora wondered aloud. He heard a slight whine and looked to his spirit. He bent down to her, scratching behind her ears. "You're right, what was I thinking? It's way too far even for someone as energetic as you. Don't worry, I'll think of another way…"

Just then, a light shone down on them. They looked up to see a massive ship that almost looked like a bridge.

"Whoa…" Sora whispered in awe as it touched down.

A ramp slowly descended from the ship's door. Sora looked to Yakumo, giving her a quick nod to say hide. She poofed away just as four soldiers in black walked up to him.

"Another stray." One grunted mechanically.

"Well, I am a little lost." Sora shrugged with a laugh. He looked between them as two of guards went to his other side. "Say, you guys going to that city down there? I need a lift."

Just as he said that, the two guards from behind grabbed him, lifting him up so they could easily carry him to the ship.

"So I guess that's a yes? Great! …I can walk by myself though. You can put me down…"

Sora wasn't too surprised to find out it was a prisoner ship. He didn't really mind it since it was still taking him into the city, where he wanted to be in the first place.

He heard from his fellow inmates that they were to participate in some games for the entertainment of other programs. Judging by their grim tone, Sora knew these weren't ones to goof around in.

The boy was shoved out onto a wide road, reminding him of a racetrack. It was surrounded by programs cheering on competitors.

"You're in luck. Only a precious few are granted Light Cycle battle privileges."

He turned to see a man wearing a slightly more dignified version of the soldier's uniform. Unlike the others, he didn't wear a helmet. It was like he wanted the programs to see the face of who'd put them here.

"Light Cycles?" Sora asked in confusion as he was given a stick-like object. It beeped at the touch of his hand.

"Incredible devices." Clu smiled. "Let me show you."

Two Light Cycles suddenly sped past them, causing Sora to jump in surprise. He noticed each driver held onto a stick like he did, except it was split into two handles.

"Let's give it a try!" Sora told himself. He ran forward before leaping into the air, pulling apart the device. A Light Cycle appeared underneath him and shot forward the moment he landed on the seat.

He grinned as two cycles sped past him. "It's on!"

He revved up before shooting past one. He was quickly gaining on the other. "Alright! This is fun!"

Just as he said that, the cycle and rider in front of him was shot by a blot of light and quickly disintegrated.

"I take it back!" Sora called, looking behind him to see a giant Nightmare hovering over him.

He slowed slightly to face the beast, wondering how he'd fight it on a bike before noticing the cycle had a projectile launcher button. That would work.

The boy slammed his thumb down on the button and fired, hitting the Nightmare over and over again.

When it seemed about ready to fall, Sora leapt off the Light Cycle, summoning his keyblade and giving the finishing blow. "And that's game over!"

He was quite proud of himself until he realized he'd dropped the handle of his cycle, making it vanish. He had nothing but the ground to catch him! "Ahh!"

Where he expected the hard ground, a car made of the same technology as the cycles caught him.

"Nice landing!"

Sora scrambled to get upright and put on his seatbelt before turning to see a young man driving. "Nice timing! I'm Sora!"

"The name's Sam!" The guy said with a grin. "One of my dad's inventions told me another User was on the grid so I came to see if you needed some help!"

Sam shot through a nearby wall, getting them off the track and away from the game.

"Don't worry, I've already got a way back home!" Sam said, making Sora frown. "The portal!"

Sora looked to where he was pointing to see a beacon of light glowing in the distance. A route to another world? The best place to find a keyhole. "Okay, I'm coming with!"

"Oh no…" Sam whispered, the car skidding to a halt when they'd made it deep into the city. He hopped out before running over to a man in a brown cloak who was leaning over an unconscious woman. Sora quickly followed suit.

"Dad, what happened?!" Sam gasped, kneeling down beside him. He then noticed something was missing from his father's back. "Your disk, it's gone…"

"It is." Flynn mumbled, not wanting to elaborate further. "As for Quorra, we got into a battle, ending with her like this…"

Sora saw the man's eyes trail over him in suspicion. He gave a wave. "Uh, hi. My name's Sora! Sorry about what happened to your friend…"

"He's the User we picked up, I told him he could come with us to the portal." Sam explained quickly. Now that introductions were out of the way, they could focus on the more important issue. "We have to go back and get your disk. It's the one and only key to the portal and CLU will use it to get to our home. I can stop him from destroying it if you'd just let me-!"

"You've done enough already!" Flynn growled in anger, gesturing to the motionless Quorra.

Sam deflated.

Sora glanced between the two nervously, feeling rather awkward.

Flynn glanced away, realizing he was wrong to take his frustrations out on his son.

"… What if we got a solar sailer?" Sam suddenly asked, thinking of an idea how to get out. "A full-out sprint to the portal! We can beat CLU there!"

Flynn looked hesitant but then glanced down at Quorra. She would've believed in Sam's idea no matter what… "Alright, let's get out of here."

A few minutes later, after stealing a sailer and reassuring everyone Yakumo wasn't like the dark spirits they'd faced before, they were soaring through the city.

Sora sat beside Yakumo who happily held her tongue out against the breeze, her tail wagging.

"Is she gonna make it?"

"I don't know."

The boy turned to see the father and son kneeled over their friend. Wish I could help, but I don't know a thing about technology…

He army-crawled his way beside them to see a hologram of Quorra pop out from her chest. "Flynn, did you write Quorra's code?"

Flynn didn't even glance up, still focused on Quorra's code. "Some of it. But the rest… is just beyond me."

"How come?" Sam asked, surprised that the famous Kevin Flynn was stumped by any problem, at alone a coding one.

"She's an ISO, the very last one." Flynn muttered softly, the clicks and beeps from Quorra nearly drowning him out. "ISOs were a whole new life form entirely. They manifested, like a flame. They weren't really…really from anywhere. The conditions were right, and they came into being. For centuries, we've dreamed of a pure existence beyond our own. I found them in here, like flowers in a wasteland. They were spectacular. Everything I'd hoped to find in the system—control, order, perfection—none of it meant a thing. The ISOs—they were gonna be my gift to the world."

At that moment, he finished Quorra and gave her time space to reboot.

A person so unexplainably pure and bright, who changed your life after coming out of nowhere…. Sora thought. He imagined Riku would be a blushing mess at hear it. That sounds like Riku, even if he doesn't believe it. … I'd bet Kairi'd agree with me. "What happened to the ISOs?"

"CLU. CLU happened. He was created to build the perfect system. The fact that ISOs could change that system scared him. And so, he wiped them all out."

"He ruined everything." Sam muttered in anger.

"No, I did." Flynn whispered. "I ruined everything in my search for perfection. I couldn't see then that it was right in front of me…"

Sora saw him gazing at Sam and Quorra and understood. Part of him wondered if Xehanort, their main enemy, was in a similar situation. If so, who'd he lost sight of in his pursuit for Kingdom Hearts? For perfection?

Just then, a spotlight hit the sailer, they'd been found.

"What's happening?" Sam asked as the sailer suddenly shifted tracks.

"They're trying to catch us before we make it to the portal, come on, we gotta move!"

Quorra slowly opened her eyes as they got down from the sailer, seeing the blinding light of the recognizer ship above her. She thought her previous stunt would've bought them enough time to escape. It probably would've if they hadn't been so focused on fixing her.

They ducked behind some crates as the ship door opened, revealing a single soldier.

"Rinzler." Sam told Sora.

Quorra looked between the guard and her friends before smiling sadly. She gave her disk to Flynn. "Goodbye."

"What- Quorra!" Sam yelled as she ran off.

Rinzler captured her easily, seeing as that was her intent, CLU would be distracted with an ISO in his hands.

"No, Quorra!" Sam cried. Flynn grabbed his son and Sora before they could go after them.

"She made her choice." Flynn mumbled in acceptance, but they could tell it irked him too. "We've got to get you guys to the portal so you can shut it off from the outside."

"But Quorra comes first!" Sam insisted angrily. "Besides, we still need to get your disk back!"

"He's right." Sora nodded eagerly. "We should get the disk before CLU has the chance to use it!"

Flynn looked reluctant but nodded.

"Meet us at the flight deck with a set of wheels!" Sam called as he ran off with Sora.

"Wheels?" Flynn muttered in confusion. "What's your plan?"

"I'm a User. I'll improvise!" Sam grinned back. Flynn couldn't help but smile back, hearing the same line he'd given Tron a long, long time ago.

"We have to save Quorra, too!" Sam said once they were out of earshot.

Sora nodded. "Yeah, of course!"

The Throneship where the disk was stored was quite small and they were able to find the disk in the center of the deck.

"There it is!" Sora cheered, running to it. The moment he touched it though, loud alarms started blaring through the ship. Rinzler was there in seconds, Quorra was being held tightly by one arm.

The boy tugged the disk away before tossing it to Sam. "Go long!"

Just Rinzler as was about to go after him, a over-inflated Yakumo pounced on him, making him release Quorra.

"What are you-?!"

"No time to explain, we gotta get to the flight deck!" Sora called, grabbing her hand as he ran past. He looked back to see Yakumo expecting praise. "Good girl, Yakumo!"

She barked happily in response.

They'd finally made it to the portal, but so had CLU.

He stood between them and the portal, believing he'd won now that Flynn had arrived.

It took Sora a few moments to realize the obvious, CLU had Flynn's face. In fact, he looked to be a younger version of him. The same way Sora had met his younger self in Monstro. But he knew just like he did then even if they looked similar, this was an entirely different person all together.

"This is mine." Kevin told them before walking up to his creation. "…Had a feeling you'd be here."

"You!" CLU hissed. "You promised we would change the world… together! So why am I alone?! You broke your promise!"

Sam knew how CLU felt. When he believed his father had also abandoned him, he was so angry and upset. It was only till after he realized Flynn had been trapped in The Grid that he could mend his relationship.

"I took the system to its maximum potential…" CLU grinned crazily as a giant monster formed behind him. "And now you will see the applications at my disposal!"

"I can't believe it…" Flynn whispered, backing away slightly as the Nightmare loomed over him.

Sora summoned his keyblade and spirit before walking past the two. "Leave it to me!"

The Nightmare looked like a grasshopper head had been stuck atop a child's spinning top, it didn't look too happy about it.

Sora dodged the various projectiles and bombas thrown his way before quickly scrambling to shelter underneath the top's edge, using it as an umbrella.

When he noticed his attacks weren't working, he scanned the beast for anything that was vulnerable. His eyes then caught on its upper body.

Yakumo gave him a boost up onto the spinning part and after a few moments of dizziness, Sora managed to pounce onto the Nightmare, climb up it, and finish it in a few big blasts of darkness.

"Nice work-"

"NO!"

Sora turned from petting his spirit to find CLU had snapped, that had been the last straw, the last chance he had at making Flynn surrender.

"I did exactly as you asked," He wailed, walking towards his creator. "I created the perfect system!"

"The thing about perfection is that it's unknowable." Flynn muttered with a sad shrug. "It's impossible, but it's also… right in front of us all the time."

He smiled back at his son and Quorra, hoping they could understand what he was trying to say.

"…You wouldn't know that because I didn't when I created you. I'm sorry, CLU. I'm so sorry."

For just a moment, it looked as if CLU may accept the apology. And then his face was full of rage. He kicked Flynn in the knee, causing the man to fall.

Sam tried to tackle CLU before he could deal another kick but was quickly thrown towards the portal. Sora ran up, prepared to guard his friend. "I don't think so!"

Quorra knelt down to her mentor in worry.

"Go." Flynn whispered softly.

Quorra hesitated for a moment, wondering why he wanted her to go to the real world. But when she turned to see Sam, she knew.

The woman blocked CLU from the young men just as he was about to attack.

"CLU!" Kevin called suddenly, making him turn. The man narrowed his eyes. "Remember what you came for…"

CLU walked back to him, the bridge disconnecting from the others as he did. He kicked Flynn once more before snatching the disc off his back. "You knew I'd beat you… And still you did all this? For him."

"Dad!" Sam yelled.

CLU smirked as the data appeared but then his eyes widened in shock. "No…"

He glared back to see Sam, Flynn's most prized creation, holding his disk, they'd swapped them. "No! Why?!"

"He's my son." Flynn answered simply.

CLU raised the disk to strike him but suddenly changed his mind, running at the three.

"Go!" Flynn yelled as CLU leapt over the gap.

"Dad!" Sam sobbed as Quorra held him back.

Sora had to guard quickly to save the others from CLU after he climbed up. "Flynn!"

"Sam, it's time!" Flynn insisted, rising to his feet. "Take her!"

"No!"

"Sam, it's what he wants." Quorra whispered.

Quorra handed Sam the disc, and it was only then he realized there really was no way to save his father. He had to be thankful for the time they had.

The father and son exchanged one last look before Sam raised the disk over his head.

CLU suddenly managed to shove Sora aside, causing the boy to slip off the bridge. He was able to grab the edge just in time. "Whoa!"

Seeing his son in danger by his clone, Flynn placed one hand on the bridge, the other on the edge. He glowed with a bright light.

"Flynn!" Sora yelled, realizing what he was doing. CLU was a part of Flynn and so their fates would be the same. He couldn't help but think of his own union with Roxas as he saw CLU disappear into the light.

"Goodbye, kiddo…" Flynn smiled sadly at his son as they watched each other leave the Grid for good. The light burst out from him, blinding them all.

Sora opened his eyes to find himself faced with the keyhole of the world. He took a step forward as the keyblade summoned itself, feeling Riku and Kairi's sadness as well. Flynn's sacrifice reminded him far too much of Kairi's back in Hollow Bastion. He never wanted to fail to keep her or Riku safe, not ever again.

With that thought on his mind, Sora went on to the next world.