(Birthright is seen flying as he then sees a building, and then he lands on its top.)

Birthright: Wow! That's so cool!

(Unbeknownst to him, a drone is spying on him, and the scene cuts to Neo H.Y.D.R.A.'s Base, where Nancy is seen watching the footage of Birthright in the top of a building.)

Nancy: Well, well, well, look who it is. It's my son who finally became a Kamen Rider at last.

(Then she presses a button, and a screen appears as Azu is shown.)

Nancy: Summon MetsubouJinrai.Net here.

Azu: Right away, ma'am.

(Then the MetsubouJinrai.Net members come in.)

Horobi: You called us?

Nancy: Yes. It looks like my former son has finally become a Kamen Rider, and he's apparently determined to help the Reiwa Riders. Well... I want you to beat him and bring him to me!

Jin: Yes, ma'am.

Naki: Leave it to us!

(As MetsubouJinrai.Net leaves, Crossbones comes in dragging an unconscious boy named James Romanoff Barnes (A.R. James Romanoff Rogers).)

Crossbones: I brought the son of Black Widow and Winter Soldier, just as you ordered.

Nancy: Good. Take him to the capsule, and get in one too. It's time for your reward!

Crossbones: (nods) Understood.

(Back to Birthright, he is seen landing on his feet as he is approached by the Reiwa Riders.)

Zero-One: This is only the beginning.

????: Of your doom, you mean, right?

(The Reiwa Riders turn to see MetsubouJinrai.Net.)

Horobi: Time for extinction!

(They prepare to transform.)

FORCERISER!

POISON!

WING!

JAPANESE WOLF!

DODO!

H/J/N/I: Henshin!

FORCERISE!

STING SCORPION!

FLYING FALCON!

JAPANESE WOLF!

BREAK DOWN!

(They become Kamen Rider Horobi, Kamen Rider Jin, Kamen Rider Naki and Kamen Rider Ikazuchi.)

Horobi: Let's begin!

Zero-One: There's only one team who can stop you, and that's us!

Vice: Didn't you mean five or six?

Revi: Shut up and let us speak our catchphrases!

Saber: We will decide this story's ending!

Revi: Let's go at once!

Geats: Now, the time has come for highlight.

(They start fighting as both Zero-One and Horobi clash while Jin dodges Saber's attacks. Naki holds his own against Revi and Vice.)

Vice: (to Birthright) Aren't you gonna do anything?

Revi: (stern) Shut up and fight, Vice!

(Geats is seen shooting Ikazuchi, who deflects the bullets. Birthright is seen just standing as he suddenly starts flying, which distracts Horobi, and then Zero-One kicks him. As Birthright lands, he prepares to punch Horobi.)

EAGLE PUNCH!

(Birthright prepares to punch Horobi, but Jin kicks Saber and takes the hit for him.)

Horobi: (shocked) JIN! NO!

(Birthright punches through Jin, and then he's reverted back to normal as he passes out. Ikazuchi and Naki rush to attack Birthright, who then prepares another finish.)

STAR AND STRIPES!

(Then an american flag appears out of nowhere, and Birthright, kicks it, causing the stripes to bind Naki and Ikazuchi, and then the stars shower upon them, reverting them back to normal as well. Horobi then tries to attack Birthtight, but Buffa stops him.)

Horobi: What the hell?

Buffa: That's enough for now! Time to retreat.

(Buffa kicks Horobi in the gut, and knocks him out before Storious shows up and takes the unconscious Jin, Naki and Ikazuchi.)

Storious: You may have won the battle, but you already lost the war.

(Storious and Buffa then leave with the unconscious MetsubouJinrai.Net.)

Birthright: (in mind) Something tells me I haven't seen the last of them...

(Back to Neo H.Y.D.R.A. Base, four kaijins are seen in their capsules. But one of them seems to be struggling as Nancy decides to speak.)

Nancy: Longing. Rusted. Seventeen. Daybreak. Furnace. Nine. Benign. Homecoming. One. Freight car.

(Then the gremlin kaijin stops struggling as Nancy smiles.)

Nancy: Good morning, soldier.

(Then the capsules open as the four kaijins get out of them.)

Rumlow: I feel more powerful than before.

Juniper: (hisses) I can finally have my revenge on that cheating bastard...

Klisman: Hail Neo H.Y.D.R.A.!

James: (bows) Ready to comply.

Nancy: I have a mission for you. Sanction and extract. No witnesses.

Rumlow: Roger that.

(Suddenly a portal opens up, and a Dark Rider comes in.)

Nancy: Who are you?

D. Primordial: I'm just a passing through Dark Rider who loves female villains. Remember that, dear.

Nancy: Hmm, I like you. But what brings you here.

D. Primordial: I'm here to deal with MetsubouJinrai.Net!

Nancy: Why would I let you do this?

D. Primordial: Because they will betray you!

Nancy: I see... I'll let you know if they actually dare betray me.

D. Primordial: No need. I'll be there when this happens.

(The four kaijins leave for their mission as the screen fades out.)