(In a certain house, we see Tassel sitting in his chair as he finishes reading a book. Behind him are the four protagonists of Reiwa Era: Aruto Hiden, Touma Kamiyama, Ikki Igarashi and Ace Ukiyo. Tassel then turns to the readers.)

Tassel: Bonne Lecture. I'm Tassel, and these are the main protagonists of the Reiwa Kamen Rider Series so far.

Aruto: My name is Aruto Hiden. I'm the protagonist of Kamen Rider Zero-One. I fought magias, rogue humagears, and even a powerful enemy only I could stop... Ark. I believe in a world where both humans and humagears can coexist.

Touma: Hi, I'm Touma Kamiyama, main protagonist of Kamen Rider Saber, and the one who decides the endings of each story. I faced various Meggidos, and even fought Master Logos, who became Kamen Rider Solomon.

Ikki: (thumbs up) Call me Ikki Igarashi. And...

(Suddenly Vice comes in.)

Vice: And I am Vice, Ikki's inner demon. Together, we protagonize Kamen Rider Revice. We fought deadmen, faced our archenemies and even worked together.

Ace: Ikki was right, Vice. You're give me a run for my money... (sighs) anyway... (turns to the readers) And I am Ace Ukiyo, protagonist of the recent Kamen Rider Series known as Kamen Rider Geats. I became a Champion of Desire Grand Prix for years, and I also reincarnated several times as well. I faced Jyamatoes, my own father, and even met one of the Heisei Riders, Kamen Rider Ryuki.

Tassel: Well, now that you all introduced yourselves, let's go to the topic of this story.

(In Earth-2345, a young boy named Percy Howard is seen holding the body of his deceased brother Michael Howard as he cries.)

Percy: Brother... I'm so sorry, brother...

(Michael Howard, Percy's brother was killed by some Neo H.Y.D.R.A. soldiers led by his own mother Nancy Olsen Howard, who personally killed her own husband Thomas Howard.)

(Inside of Neo H.Y.D.R.A. Base, Nancy is seen in her office as she sighs and looks at the picture of her own son.)

Nancy: My son, I'm sorry to disappoint you that your brother has to die!

(Suddenly Eddie Rumlow/Crossbones comes in holding a flask.)

Crossbones: Here's the flask you asked me, ma'am.

Nancy: Perfect.

(Nancy picks up the flask.)

Nancy: I'll call you when I need you again. Now leave!

(Crossbones nods and leaves as Nancy prepares something devious with the flask.)

Nancy: (smirks) I am now CEO of Neo H.Y.D.R.A. Coop., no one shall stop me from making my own monsters.

(Some days later, a new coronavirus was unleashed, and half of the population became infected while the other half tried their best to protect themselves from the new coronavirus.)

(Back to Percy, he is seen feeling hopeless.)

Percy: If only I could something... anything to put an end on this nightmare...

????: You can do something.

Percy: Huh?

(Percy turns to see the Reiwa Riders: Zero-One, Saber, Revi, Vice and Geats.)

Zero-One: We are here to help you to stop your mother.

Percy: My... mother?

Saber: She's the CEO of Neo H.Y.D.R.A., and the one who ordered the murder of your brother.

Percy: (eyes widen) WHAT?

Vice: She was also the responsible for this new coronavirus being unleashed worldwide.

Revi: And now she's planning to create her own kaijus.

Geats: We choose you to become the new Reiwa Rider.

Percy: Me? But how?

(Suddenly Geats gives him an Eagle Trinket, and suddenly a Miraidriver is summoned.)

Percy: Are these...

Reiwa Riders: They're all yours, Percy. Now become a Kamen Rider and save the world.

Percy: (nods) Hai.

(Percy then remembers his brother and father as he promises to avenge them and save the world from his former mother.)

Percy: Henshin!

TRUTH! JUSTICE! AMERICAN WAY! KAMEN RIDER BIRTHRIGHT!

(Percy becomes Kamen Rider Birthright.)

Zero-One: This is...

Saber: Your power...

Revi: To save...

Geats: The world.

(Then Brithright raises his fists.)

Birthright: For truth, justice and the American Way! Kamen Rider Birthright!

(Then he walks out of his house and realizes that his Kamen Rider Form makes him immune to the coronavirus as the Reiwa Riders approach him.)

Zero-One: Oh, we forgot to add the detail. While we're in our Kamen Rider forms, we're immune to this new coronavirus.

Birthright: Well, let's see what else it can do.

(Birthright jumps off and suddenly realizes he's flying.)

Birthright: (excited) Hey, I'm flying!

Saber: The new Kamen Rider can fly?

Revi: By himself?

Vice: Just like Skyrider.

(Then everything stops and goes gray as the scene shifts back to Tassel.)

Tassel: Well, the new Kamen Rider is testing his new Rider Powers. But does he actually have time for this? Maybe some enemies will wait the moment to strike. But that's going to happen in the next chapter.

(Suddenly Woz appears out of nowhere.)

Woz: IWAE! A new Kamen Rider in town in Megaforce-Verse known as Kamen Rider Birthright, this guy's name is Percy Howard the American Eagle Rider & Enemy/Son of Nancy Olson Howard/ Kamen Rider Corona. He's gonna be both allied with DaiKaiju-Verse & Megaforce-Verse, Allies with Reiwa Riders: Zero-One, Saber, Revice and Geats. For Truth, Justice and American Way!

Tassel: (sighs) I forgot Kamen Rider Zi-O has allied with Zero-One once. Well... see you in chapter 1.