We cut to a warehouse where police cars pull up to the scene. Several officers armed with shields are holding their ground as three Gurongi creatures attack. As the cars come to a halt, a young woman steps out, drawing her gun and aiming it at the creatures.

??? (Ai): FIRE!

Ai Yashiro! The Detective! And the ally of Kamen Rider Kuuga!

All the officers begin firing at the Gurongi. Two of the creatures recoil from the bullets, but one of them presses forward, unfazed, charging toward the officers. Ai quickly grabs the walkie-talkie from the car.

Ai: Unidentified Lifeforms No.14, No.21, and No.24 confirmed! Yusuke, do you copy?

Cut to a young man riding a motorcycle through the warehouse. He’s racing toward the scene, the Police officers continue firing at the Gurongi, struggling to hold their ground as the creature moves in closer. The young man arrive in time.

??? (Yusuke): Sorry I was late!

Yusuke Odagiri! The Smile Protector! A.K.A the A.R Kamen rider Kuuga!

Police Officer 1: Huh? Who are you?! Get out of here, it’s dangerous!

Ai: Don’t worry, he’s with us.

Police Officer 2: What?! What are you talking about? He’s just a kid!

Yusuke (smile) She’s right. I’m just an ally who wants to help! (Places his hand at his waist as the Arcle belt suddenly appears. He places his hand over it) Henshin!

Yusuke then started to run at the three Gurongi, striking a henshin pose. As he activated the Arcle, the armor began to materialize.

Pieces of red and gold forming around his body with a radiant glow. His transformation into Kuuga was complete.

Police Officer 3: (Shock) What?! Unidentified Lifeform No. 4?!

Ai: (Smile) Yes, that’s right! He’s on our side. Everyone, hold your fire!

Police Officer Police 1: R-Right!

The officers look at each other, still surprised but lowering their weapons.

??? (Me-Vagis-Ba): (In Gurongi Language) Kuuga!

??? (Me-Geega-Gi): (In Gurongi Language) Our target is not him! Focus our goal!

??? (Me·Garido·Gi): (In Gurongi Language)  He really love to ruin our fun...

Kuuga: I have no idea what are you guys speaking but I will stop you three! (charged at the Gurongi)

Kuuga swiftly executed a  kick to Me·Garido·Gi, sending the creature staggering back. As he followed up with a punch to its chest, a sudden attack came from behind.

But Kuuga was quick on his feet. He delivering a kick that sent Me-Geega-Gi crashing into a nearby wall. Kuuga expertly dodged the incoming attack, feeling the rush of wind as Me-Vagis-Ba narrowly missed him. With a fierce determination, he retaliated, launching a flurry of punches to Me-Vagis-Ba's gut, landing three solid hits

Y/n: (ride his bike and arrive at the scene) This is Kamen Rider Kuuga and Gurongi? This is amazing...

Kuuga continued the fight as he kneed Me-Garido-Gi in the gut. He followed up with a powerful elbow strike to the creature’s back, sending it stumbling forward. In one swift motion, Kuuga kicked Me-Garido-Gi straight into Me-Vagis-Ba, the impact causing both Gurongi to crash to the ground.

But just then, Me-Geega-Gi capitalized on the moment, launching a brutal attack. It landed two heavy punches to Kuuga’s gut, forcing the Rider to double over. Before he could recover, Me-Geega-Gi swung a fist that struck Kuuga square in the face, sending him crashing through the entrance of a nearby warehouse.

As Kuuga staggered to his feet, his heart sank at the sight before him. He spotted the lifeless body of a police officer.

Kuuga: What?! They’re targeting policemen?! First a policewoman, now a man?! What are they doing?!

Y/n: (take his camera) Just like Episode 1 of the show...

Ai: (Spotted Y/n) Hey! What are you doing there? It's dangerous!

Y/n: (looking at Ai then Smile) Don't worry i'll be fine (thought) Guess I gonna help Kuuga. (take Original Decadedriver)

Ai: (confused) What are you doing? And what is that belt?

Y/n placed it around his waist, the strap wrapping itself securely. The Ride Booker appeared on the left side of the Driver.

Y/n take out Kamen Ride Decade card then Y/n grabbed the side handles and pulled them, causing the Decadriver to rotate open.

Y/n: Henshin! (flipping the card to the backside)

He inserted the card into the Decadriver.

Decadriver: Kamen Ride!!!!

Y/n placed his hands on the side handles and pushed them down to close the driver.

Decadriver: Decade!

Suddenly, silhouettes of the Heisei Rider symbol and Decade armor, began to appear, merging with Y/n. The armor formed around him, and a barcode emerged from the driver into his helmet, completing his transformation into Decade.

Ai: Eh?! Are you Kamen Rider?!

Decade: (checking out his suit) YOSHA! I actually transformed into Decade!!! This... is the best day of my life! (To Ai) Heh... I guess you can say that, but really... I’m just a passing-through Kamen Rider!

Kuuga: (spot Kamen Rider Decade) Eh?! Another Kamen Rider?

Me-Vagis-Ba: (in Gurongi language) Nani?! Another Rinto Warrior?!

Decade: Yosh... Let's do this! (take Ride Booker in Sword Mode) IKUZE, TEMERA!!! (charged at the Gurongi)

(Ride The Wind Playing)

Decade then charged at the Gurongi as he slashed Me-Vagis-Ba, then slashed Me-Garido-Gi. He slashed Me-Geega-Gi two times, spun around for a kick, and then slashed him again.

Me-Vagis-Ba shoot needle attack at Kuuga, he shoot and destroy the Needle, Me-Geega-Gi punch Kuuga but he block it, and Decade punch Me-Geega-Gi twice.

Me-Geega-Gi then fired globs of ink at Kuuga and Decade, which exploded upon hitting the ground. Both Riders dodged it as Me-Garido-Gi tried to attack Decade, but he dodged the attack.

Decade then slashed him three times, punched him four times, and slashed him five more times. Kuuga then punched Me-Vagis-Ba in the chest twice and followed up with a punch to the face.

As Me-Geega-Gi tried to attack, Kuuga dodged and kneed him in the gut, then punched him in the face twice. He kicked Me-Vagis-Ba in the back as Decade turned his Ride Booker into gun mode and started shooting at Me-Garido-Gi, causing him to stagger back a little.

Decade kept firing at Me-Vagis-Ba and Me-Geega-Gi, each shot causing them to stagger back, struggling to keep their footing against the relentless barrage. Meanwhile, Ai looked around, her attention suddenly caught by the roar of an approaching motorcycle engine.

Then, from the police car's radio, a voice crackled to life.

Radio: Attention to all officers on site. G1 has been launched and is en route to your location.

The roar of the motorcycle grew louder, reverberating through the area as all eyes turned toward its source. The police and Ai watched in anticipation as G1, the armored figure on the bike, sped past them, heading straight for the warehouse.

Ai: (Smile) Ichijo... You finally arrived!

Inside, the battlefield was tense. Decade held his Ride Booker in gun mode, aiming it at the Gurongi, while Kuuga stood in his fighting stance, prepared for the next attack. Suddenly, the three Gurongi were blindsided as the motorcycle burst into the fray, hitting them hard from the side.

Kuuga and Decade turned, watching as the figure on the motorcycle hopped off, landing gracefully.

???: (arrive) Sorry I was late! (Spot Decade) Eh?! Another Kamen Rider?

Kuuga: (Happy Tone) Ichijo-San!

G1: So who is that Kamen Rider? (point at Decade)

Kuuga: His name is... Ano...

Decade: Decade. Kamen Rider Decade, the one passing through worlds of Kamen Riders. Remember that.

G1: Decade, huh? I’m Kamen Rider G1.

Decade: (Thought) This world... has a G1 who's fighting alongside Kuuga?! Awesome! (out loud) Well, it's nice to meet you guys, actually... You two can think of me as your kouhai.

Kuuga: Eh?! Kouhai?

G1: That's new... I guess you are the new Rider?

Decade: I am! If you want to see something cool, I can show you!

Kuuga: Really? What is it?

Decade smirked under his helmet as he opened the Ride Booker and pulled out the Kuuga card. He then pulled the handle to open the Decadriver.

Decade: Henshin! (He flipped the card to the backside)

Decade inserted the card into the Decadriver.

Decadriver: Kamen Ride!!!

He placed his hands on the side handles and pushed them down to close the driver.

Decadriver: Kuuga! (Arcle Mighty Form transformation sound)

the Kuuga armor began to materialize from his body. Pieces of red and gold formed around him with a radiant glow, completing his transformation into Kuuga.

Gurongi: (In Gurongi language) Nani?! Another Kuuga?!

G1: You can change?!

Kuuga: Uso daro... You... you just transformed into me!

D-Kuuga: Yep! I can transform into any Kamen Rider including you, Kuuga.

Kuuga: Sugee....

D-Kuuga: Now... Ready to continue the fight?

G1: Three versus three now it's fair! Ikuzo!

Kuuga: Yosha!

Decade, Kuuga, and G1 charged at the Gurongi as D-Kuuga punch Me-Geega-Gi five times, the Squid Gurongi scream in pain and Kuuga drop kick at Me-Garido-Gi, he yell in pain.

G1 punched Me-Geega-Gi in the chest, then in the face, followed by an elbow strike. He then punched him in the face again and continued to punch him in the chest repeatedly.

D-Kuuga punch Me-Garido-Gi twice before headbutt his face, the Gurongi yell in pain and D-Kuuga grab Me-Garido-Gi in the air, and Kuuga perform bicycle kick at Me-Garido-Gi in the air, leaving Me-Garido-Gi yell in pain and land in the ground.

Kuuga kicked Me-Vagis-Ba in the face, then delivered an elbow strike to the Gurongi's face, followed by a punch to the gut. He then punched him repeatedly in the chest before grabbing him and delivering a knee strike to the gut. Finally, Kuuga threw him against the wall and punched him in the face.

Me-Vagis-Ba: Try to defeat me in the air! (shoot needle stinger at Kuuga)

Kuuga: (Dodging the needle stinger) I don’t know what you said... but I accept it!

G1: Yusuke! Use this! (throw his spare Pistol at Kuuga)

Kuuga: (Grab it) Arigato, Ichijo-san! (Looking at the gun) Yosh... Chou HENSHIN!

Kuuga's body started to glow green as his armor began to change, and the spare pistol transformed into a new weapon.

Me-Vagis-Ba shoot needle at Kuuga, he dodge it. Kuuga focus on his mind and charged his shot before he shot arrow at Me-Vagis-Ba, the arrow hit at his chest, Me-Vagis-Ba yell in pain and say his last words.

Me-Vagis-Ba: D-Damn you! (explode)

D-Kuuga: Awesome...

But then the Decadriver opened itself, and the card ejected from the driver, turning D-Kuuga back into Decade. Decade caught the card as it became blank.

Decade: Aw man... Just like Kamen Rider Decade, it turn blank...

Me-Geega-Gi fired globs of ink at Decade, who was just standing there. G1 quickly pushed Decade away.

G1: Decade! Watch out!

Decade: ?!

G1 got hit by Glob of Ink from Me-Geega-Gi, he is knock back on the ground and the Riders are shock, they check on G1.

Decade/Kuuga: (Worry tone) G1!/Ichijo-San!

G1: Ugh... I'm okay, guys!

As G1 tried to get up, part of his helmet broke off, and smoke began to escape.

Kuuga: Are you sure you're okay?!

G1: I'm fine! Trust me!

Decade: Omae... Yurusan... (He looks at Me-Geega-Gi) Kuuga-senpai, let me handle that guy.

G1: And I'll handle the other one...

Kuuga: What?!

G1 placed his hands on Kuuga's shoulders and looked him in the eye.

G1: Odagiri! Just trust me! I'm definitely going to defeat him and show the police what the G1 system can do!

Kuuga: I understand but please be careful.

G1: (Smile) Thanks for trusting me!

Kuuga: Don't worry about it!

Decade: (Thought) Since Kuuga's card can't use it... I guess use other card.

Decade then pulled out another card from the Ride Booker; it was the Final Attack Ride card. As Me-Geega-Gi and Ma-Garido-Gi started to run away, Decade noticed this.

Decade: Oh no, you don't!

Decade began to chase them. He pulled the handle to open the Decadriver as G1 went to his motorcycle and grabbed a GM-01 Scorpion. He started shooting at Ma-Garido-Gi multiple times, causing him to yell in pain. Each time Ma-Garido-Gi tried to get up, G1 kept shooting at him.

Meanwhile, Decade caught up with Me-Geega-Gi. He punched the Gurongi in the face, then in the gut, followed by an opposite sequence of punching him in the gut and then the face again. When Me-Geega-Gi tried to attack, Decade blocked it and then pinched him, making him stagger back.

Decade then flipped the card to the backside and inserted it into the driver.

Decadriver: Final Attack Ride!

Decade then pushed down the handles to close the driver.

Decadriver: De-De-De-Decade!

A human-scaled holographic card of the Final Attack Ride appeared as Decade jumped, the card following him into the sky. He phased through the holographic card while letting out a battle cry, striking Me-Geega-Gi. The Gurongi let out a sound of pain as he exploded.

Decade: Yosh! I did it... My first Rider Kick!

Kuuga: (goes to Decade) Good job, Kouhai!

Decade: Thanks, I guess!

G1 rushed at Me-Geega-Gi as the Gurongi tried to attack, but G1 blocked it. He hit Me-Geega-Gi with the GM-01 Scorpion and then punched him in the face. Pressing the trigger, G1 continued to fire at Ma-Garido-Gi. The Gurongi tried to withstand the attack, charging at G1 and attempting to grab the GM-01 Scorpion to throw it away. However, G1 headbutted him three times, causing sparks to fly from the helmet.

G1 then grabbed Ma-Garido-Gi and headbutted him again, breaking the helmet and revealing Ichijo's face. G1 punched Ma-Garido-Gi in the chest three times before placing the GM-01 Scorpion on the Gurongi's chest. G1 started to shoot him again, causing the Gurongi to yell in pain and stagger back.

Next, G1 pulled out the GG-02 Salamander and combined it with the GM-01 Scorpion. He pumped the GG-02 Salamander and aimed it at Ma-Garido-Gi, glaring at the Gurongi.

G1: This... is for every innocent person that you killed!

G1 then pressed the trigger, launching a grenade at Ma-Garido-Gi. The grenade exploded, and Ma-Garido-Gi staggered back. G1 pumped and shot at him again, causing the Gurongi to yell in pain. G1 pumped the GG-02 Salamander one last time and fired at Ma-Garido-Gi again. The shot hit, resulting in another explosion as smoke began to cover the scene.

As the smoke cleared, Ma-Garido-Gi stood, slowly approaching G1. Ready to attack, G1 watched as Ma-Garido-Gi dropped to one knee and then collapsed to the ground, exploding.

G1: I did it...

G1 looked at Kuuga and Decade, smiling and giving them a thumbs up. Kuuga returned the gesture with a thumbs up as well. However, G1 suddenly began to collapse. Kuuga rushed to him and quickly untransformed.

Yusuke: (Caught him) You did it! You beat a Gurongi!

G1: Ugh... I think I need a medical treatment.

Ai: (arrive with the police squad) Ichijo-San! (look at the police squad) Bring him to hospital right now!

Police Squad: Yes, ma'am!

Ai: (looking at Decade) And you... who are you, exactly?

Decade: I'm Kamen Rider Decade, just a passing through Kamen Rider from another world, remember that.

Ai: What?! From another world?! And you were wearing a police outfit... So, are you really a part of the police... or are you just... an imitator?

Decade: (sigh) Did you want me to explain at somewhere else? I don't want people getting attention.

Ai: Fine... but you better explain everything.

Decade: (Nodded) I will, I promise. Just head over to 9-5 DO Studio. I'll meet you there. But for now... this is goodbye.

Decade pulls out another card from the Ride Booker, flipping it and inserting it into the Decadriver.

Decadriver: Attack Ride!

Decade: Ciao~

He presses down the handles, closing the driver.

Decadriver: Invisible!

Decade starts to back away as he fades from sight, vanishing completely.

Ai: (Awe) He just... disappeared. Another world, huh? Guess I’ll be waiting at 9-5 DO Studio.

Yusuke: Man, what an awesome Kamen Rider...

At 9-6 DO Studio.

Decade reappears, breathing heavily. He grabs the Decadriver from his waist, pulling it off, which causes him to revert to his civilian form.

Y/n: (catching his breath) Geez... It took me a while just to find my own house!

Geito: (appear behind Y/n) What took you so long to get here, huh?

Y/n: (jumps in surprise) AH! (He turns and sees Geito standing there) Hey! Don’t blame me! This is a new world! It took me a while to find it!

Geito: Dude... You left me, Shoutmon, Dracomon, Turtwig, and Chimchar behind...

Shoutmon/Dracomon: Yeah! How could you left us!

Chimchar: Chimchar...

Turtwig: Turtwig....

Y/n: I was too excited to fight a real monster, alright?! I just... kinda forgot.

Shoutmon: Next time, maybe remember we’re part of the team too!

Geito: Shoutmon is right. We maybe rival but we are part of teams.

Y/n: Alright, alright! I get it! Next time, no leaving anyone behind. Promise!

Geito: I forgive you... So what's happen? Did you meet Kamen Rider Kuuga?

Y/n: I did! Nice guy, too. And by the way, this Kuuga world… it has G1!

Geito: EH?! G1 is here too? Who is the user?!

Y/n: (Smirk) Kaoru Ichijo! That’s the user of G1! Bro, you should have been there! He was so cool as G1! And even had the Rider helmet break!

Geito: Damn... You are a lucky, Y/n.

Y/n: I know! This might be the best day of my life!

Geito: Wait! Did Kuuga call you a devil like... Onodera did?

Y/n: Now that I think about it... he didn’t call me a devil.

Geito: Hmm... Guess you change the episode 1 by helping him, and he trust you.

Y/n: Maybe you’re right! But you know... (pulls out the 9 Heisei Rider cards) Look at this... Only Kuuga's is blank. The rest... they’re okay.

Shoutmon: Oh! I remember something!

Geito: What is it?

Shoutmon: Tsukasa said you can use the Heisei Phase 1 Rider powers... but only once! He knew you’d want to test them out before getting the true Rider powers!

Y/n: So that's why... Guess I keep them for the emergency.

Geito: How about me?

Dracomon: For you, Geito-san… you can use or summon any Rider you like!

Geito: (smiles) Really?! Yosha, lucky!

Y/n: (pouts) Lucky…

Geito: Hey! It's alright, maybe you can unlock the Rider power someday.

Y/n: (sighs) I hope so...

Geito: Wanna get inside the shop?

Y/n: Sure… after that, I need a break…

Geito: Same... I think we should get inside your store...

Shoutmon: But you two deserve it! It’s one step closer to becoming true successors of Kamen Rider!

Y/n: Thank you, Shoutmon!

Shoutmon: You're welcome! After all... you're my partner! Now, let's get inside!

Y/n: Right!

Y/n opens the door, and one by one, they enter, disappearing inside. The camera begins to slowly zoom out, before the scene cuts to a dark room. In the center of the room stands a giant clock, A cloaked figure stands before it, holding an open Books, then snapping it shut.

??? (Woz): After Y/n and Geito gain the power of Zi-O, Decade, Geiz, and Diend. They both become the successor of Riders and their destiny are saving the A.R Heisei Rider Worlds.

??? (White Woz): Indeed, Kuro Woz.

Kuro Woz! The Supporter of Y/n! And Shiro Woz! The Supporter of Geito!

Kuro Woz: hope you enjoyed the first chapter of this book, dear reader. But remember... this is only the beginning.

Shiro Woz: Yes, from now. The next chapter will begin someday in the future.

Kuro Woz: See you next time, my dear reader! Iwae! Because from today onward... the Destroyer King of Time and Space has been born!

Shiro Woz: And as well... the thief who is a savior of the world! Together, they will shape destinies and rewrite the fate of many.

Kuro Woz and Shiro Woz say goodbye to the reader before the screen end with Kamen Ride: Decade and Kuuga Card on the background. The song is playing in the background.

(Ending Theme: INSIDE-OUT Zi-O Vers.)

.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
End of Prologue Part 2!
.
.
-

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------