It starts off where Y/n is not presently seen outside, but in a dream.

It shows him facing Ohma Zi-O back in his time for one final showdown, while seeing the background of Dai Mazines destroying the city.

Y/n: You won't destroy my home, because I will be king and save this world.

Ohma Zi-O: Very well. I accpet your challenge.

Y/n then puts on the Ziku Driver and grabs his ridewatch.

Ridewatch: (Digital beeping) Zi-O!

Y/n: Henshin!

Rider Time! (Electronic guitar) Kamen Rider Zi-O!

Ohma Zi-O: ...Come at me.

Zi-O: *screams as he charged*

Y/n then summoned his weapon.

"Zikan Girarde!" "Ken!"

As Y/n jumps up and attempted to attack Ohma Zi-O with his sword, Ohma Zi-O raised his hand and fired a huge powerful blast that sent Y/n through a building.

As Y/n tried to get up, Ohma Zi-O appeared in front of Y/n after he teleported.

Zi-O: No, I won't give up. I will... I will protect everyone. I...

Ohma Zi-O: A pity you couldn't stand up to me. Then allow me to close the book to your story.

Ohma Zi-O then continued to approach Y/n, while he's seen being frightened.

Zi-O: N-No, stay away! Stay away! No! NOOOOOOO-!!!

In the present...

Y/n: No... No.

Koemi: Y/n? Y/n!

Y/n then opened his eyes, and as his blurriness faded, he sees Koemi above him, which she used her knees as a pillow.

Y/n: *sigh in relief*Koemi...

Koemi: Ah... Y/n, you're okay. Thank goodness.

Y/n: Yeah, I guess so. *sits up*What happened?

Koemi: ...After that red rider left, you suddenly went unconscious.

Y/n: *thoughts*That's right, I was defeated by him.

Koemi: Are you okay? I thought you were feeling pain all of a sudden.

Y/n: No, I just had a bad dream, don't worry about it. *thoughts*Although, I wonder if that future is really going to happen...

Koemi then rushed towards Y/n and hugged him tightly.

Koemi: *sob*You idiot... You stupid idiot...! I'm so glad you're alright, but that was just reckless. *sob*If you were gone, then what would I...?

Y/n then hugs right back gently.

Y/n: Koemi... I'm sorry I worried you. You're right, I should've done better. But I'm still here, right? So please don't cry.

Koemi: *wipes off tears*...Okay.

Y/n: Heh. Anyway, what is this place?

As Y/n looked around, the area they are in only shows the sea and black clouds showing rays of light piercing from the everlasting sky. He looked around to see there is nothing around but seeing the horizon 360 degrees.

The two are sitting on the water, but they're not wet.

Koemi: I don't know, after you went unconscious I carried you and was brought to this place until you woke up.

Y/n: Brought here? By who?

???: Why, by me of course.

Y/n and Koemi were then approached by the cloaked man. Y/n and Koemi then stood up as he got close to them.

Y/n: Old man...

???: It has been a while, Y/n.

Y/n: Why are you here? Where are we?

???: This is a special space I have created from deep within my psyche. Young Koemi had a little conversation with me, and it seems you finally met your match.

Y/n: What the hell's going on, old man!?

???: It seems there's some disturbances on your journey. I never thought another Kamen Rider from the future would get himself involved in stopping you.

Y/n: The future...?

Koemi: Y/n, what is it?

Y/n: Old man.

Koemi: Hmm, what's wrong?

Y/n: There was something that guy Mitsuru, the new Kamen Rider said earlier that's bothering with me. That he came from the future, unlike in the era we live in.

The cloaked man turned to face Y/n, being surprised about this.

Y/n: However, you said that Ohma Zi-O destroyed the world at our time, 2020. I'm certain that Mitsuru guy couldn't be alive 'til then. ...Just what are you hiding.

???: *sigh*... I see how it is. Y/n, whatever you're thinking, it's not what you think it is. Back what I said about Ohma Zi-O destroying your world in that time was true.

Y/n: Then why-?

???: Your world, is a normal one, that should've been going towards a safe future. However, somehow, the event of destruction was forced onto your world.

Y/n: So it wasn't inevitable?

???: That's right. Which is why I searched for you so there's the chance of saving it.

Y/n: But, why me? I mean, of course I was motivated to be king and gain the power I need to save my world. But couldn't you choose any other?

???: The reason for that... I can't explain it to you. But I will, in time...

Y/n: Great...

???: Anyway, you have no time to waste here. Your world's destruction is still inevitable, and you still need to collect the riders' powers to save it.

Koemi: Oh, that's right. Come on, Y/n, we have to hurry.

Y/n: Alright.

Y/n then grabbed a blank ridewatch, threw it, and opened a portal.

???: Y/n. ...I will assure you that I will let you know when Kamen Rider Savior is nearby.

Y/n ignored that, and he and Koemi went through the portal.

Later...

Y/n and Koemi went through the portal and came into another world.

Koemi: I wonder where are we?

Y/n: I don't know. Come on, let's search around.

But as they walked, Y/n and Koemi are then confronted by a pack of monsters.

Koemi: Ah! What the...

Y/n: Koemi, stay back. Leave this to me. *puts on Ziku Driver*

Ridewatch: (Digital beeping) Zi-O!

Y/n: Henshin.

Rider Time! (Electronic guitar) Kamen Rider Zi-O!

Y/n then stared as the pack of monster headed toward him.

Zi-O: This isn't going to be easy. I'm going to need more firepower this time.

Y/n then picks up the G4 ridewatch.

Zi-O: I haven't tried this one yet.

Ridewatch: (Digital beeping) G4!

Y/n then inserted the ridewatch on the other side of the belt and turned it around.

Armor Time! (Epic rock music, followed by police sirens) G4!

The armor appeared in front of Y/n as a suitcase. It then showed it transforming into its physical form, showing computerized status of each part of the armor. Finally it was put onto Y/n.

As the horde of monsters charged at Y/n, he summoned his two blasters, the GM-01 Type Zs.

Y/n then fired his guns at the monsters, killing them instantly with just one shot.

Inside his helmet, Y/n sees a computerized screen of where to fire, firing at the right time, and locating their weakpoints.

After Y/n killed the last monster, a huge monster appeared fight in front of him.

The monster tried to crush Y/n, but he shoulder rolled through between the legs to get out of the way.

Y/n then combined his two guns that looks like an assault rifle, and began to rapid fire on the monster.

Y/n shoots at the monster's weakpoints and rolled out of the way everytime the monster tried to crush him.

Y/n stood while the monster got on its knees.

Zi-O: It's over, you big ugly.

Y/n pressed both ridewatches and turned his driver around.

Finish Time! G4! Launcher Time Break!

Y/n summoned 4 missles on his back, similar to the missiles from the Gigant. The missiles then launched and hit the giant monster at the same time, resulting in a massive explosion.

Y/n then realized the battle is over and de-henshins

Koemi: Y/n!

Y/n then saw Koemi coming to him.

Y/n: Koemi, are you okay?

Koemi: *nods*What about you?

Y/n: I feel great, being back on the field and all. Although, I never thought we had to encounter a lot of monsters.

Koemi: Yeah, maybe even too many.

Y/n: Something's definitely up with this world. But let's not worry about that. Let's hurry up and find a rider, and get out of here.

Later...

Meanwhile, in a wide area, there is a young man, but running away from something.

It was Otoya Kurenai, Kamen RIder Dark Kiva. But this one is unlike the original, more like a villan type.

Otoya: *pant* *pant*Damm you Decade! Don't think this is over, I know you will return to this world. And once you do, I will have my revenge.

Y/n: Unfortunately for you, that's going to happen.

Y/n then approached Otoya along with Koemi who is hiding from the background.

Otoya: You... are a human. Who are you? How are you still alive?

Y/n: I don't know what you're talking about, but I don't care. As for who I am, well, call me Kamen Rider Zi-O. But that will be the last thing you'll ever hear from

Otoya: You must have a death wish, showing your face to the likes of me.

Y/n: I really don't care what you say. But I sense you have great power. Unfortunately, I'll have to kill you to get it.

Otoya: *evil chuckling*Do you have any idea what you're dealing with.

Y/n: Who knows. But like I said, I don't care.

Otoya: Oh, you should be.

On a ledge, Kivat-bat the 2nd was hanging on a ledge. Then he flew to Otoya and put his hand.

Kivat-bat the 2nd: Gaburi!

Otoya then transformed into Dark Kiva.

Y/n: Interesting, then I'll just have to up my game. Now then, bow down to your king.

Y/n then transformed to Zi-O immediately and the transformation was quick.

Zi-O: I believe your time... is up.

With that, Y/n and Otoya begin to battle.

So far, all Y/n and Otoya are just hand-to-hand combat.

Both seem to have equal power, beating each other up.

Zi-O: Looks like you're strong because you have dark power. How about I turn this to a fair fight.

Y/n grabbed the Dark Ghost Ridewatch.

Ridewatch: (Digital beeping) Dark Ghost!

Y/n then repeated the process he did earlier and it happened again.

Armor Time! (upbeat music based on Ghost Driver's standby music) Kaigan! Dark Ghost!

Y/n's armor appeared right in front of him in his physical form. It performs to pose of spreading its arms out gracefully before it and the kanji got put on Y/n

Dark Kiva: What just happened?

Zi-O (Dark Ghost Armor): You may be a vampire, but I am a ghost.

Y/n then got more of an advantage over Otoya.

After a little bit of showing his display of might, Y/n summoned parka ghosts from his eyecon shoulders. Which are his own, Napoleon, Ikkyu, Pythagoras, and Darwin.

The 5 parka ghosts float around and kept attacking Otoya fast, each one of them.

As one of the parka ghosts hit Otoya down on the ground, Y/n pressed his two ridewatches and turned his driver.

Finish Time! Dark Ghost! Omega Time Break!

Y/n's parka ghosts first helped him lift up in the air. Then, all 5 ghosts merged with Y/n, and showing a white flame on his right foot. Y/n then ends it by performing a powerful rider kick.

Dark Kiva: No. No! I... I can't die like this! Someone, please save! M-Mommy, help! Please, anybody save me!!!

Zi-O (Dark Ghost Armor): Sorry, but no one's coming to save you. After all, you're all alone.

Dark Kiva: Just... who are you?

Zi-O (Dark Ghost Armor): Me? I'm just a Kamen Rider... who wants to be a king.

Dark Kiva: You...

Otoya then gets down on his knees and got down on the ground, which resulted in him exploding.

But after Otoya died, Kivat-bat the 2nd is alive and tried to fly away.

Unfortunately for him, Y/n catches him.

Zi-O (Dark Ghost Armor): Sorry you stupid bat, but you're not going anywhere.

Y/n then pulled out his blank ridewatch and used it to absorb Kivat-bat the 2nd. Now his ridewatch turned into the Dark Kiva Ridewatch.

Koemi: Looks like you did again, Y/n.

Y/n: *de-henshins*Thanks.

Koemi: And not only that, you helped this world too of that evil rider. I'm happy for you.

Y/n stares at his new ridewatch.

Y/n: Heh, now it really feels good to be back.

Meanwhile...

Mitsuru is suddenly seen watching Y/n and Koemi from a far and high distance.

Mitsuru: Seems Zi-O is still hunting for the dark powers of those riders. *grunt*Despite my warnings, why is he still doing this?

Mitsuru then grabbed and stared at his own ridewatch.

Mitsuru: Just what you think you're planning, Zi-O?

To be continued...