[Cut to Phineas and Ferb's hotel room, where Phineas frantically closes the window curtains.]
Isabella: so Khaka peu peu was that Mysterio guy huh?
Phineas: yea he did it because he was hoping to redeem his misdeeds, but now I have a feeling he is not as truthful as he say he is (sighs) I can't believe I gave him those glasses! I mean, how could I be that stupid? He's probably spying on me right now or sending a drone to come and kill me.
Isabella: You had access to killer drones?
Phineas: Yeah, We didn't really want 'em, especially after I almost killed Antonio.
Isabella: You almost killed Antonio?!
Phineas: Look, I have to call Major Monogram and tell him that Khaka peu peu's a fraud, but... I think he tapped my phone.
Isabella: Okay, so what are you gonna do?
Phineas: Well, I got to get Ferb, then I need my suit and I have to go to Berlin and talk to Major Monogram in person. (He opened the closet and there was the Beak suit. Isabella look a little impressed)
Isabella: how you managed to get it inside the hotel I'll never know.
[Then the camera pans over to reveal Baljeet, Ferb, and Buford standing in the doorway. The they share a glance - Isabella impassive, The boys panicked.]
Phineas: Ah! Ferb,guys, perfect!
Baljeet: The costume looks great! For the costume party, at the... Prince's castle...
Phineas: it okay she knows.
Isabella: I figured it out. It was obvious
[They hesitates, then slowly nods.]
Baljeet: Oh. That's cool.
Isabella: Like, on the nose.
Baljeet: ...oh.
Phineas: Look, Mysterio is a fraud.
Baljeet: But he- But he saved me and Ginger's lives...
Isabella: No, he's been faking the whole thing with illusion tech.
Phineas: Yeah, he's using these, like, hologram projectors.
Buford: Whoa! That's... crazy!
Isabella: Yeah.
[A beat while Phineas and Isabella share a glance.]
Buford: So, you guys were, like... working the case together, or what?
Isabella: It's been mostly me.
Phineas: Look, Guys, I need you to call Candace, get her to call Mr. Harrington, say that she wanted me and Ferb to stay with family in Berlin until this all blows over, okay?
Baljeet: Got it. Easy.
Isabella: Wow. You guys lie with such ease.
[Buford shrugs.]
Phineas: Ferb we gotta go.
[As the boys got in the suit, they starts to move out, pulling open the window curtains.]
Isabella: Wait! Ah, wait, wait, wait! The projector. You're gonna need this.
[She throws Him the projector, which he catches.]
Phineas: Don't tell anyone about this, okay? Anyone who knows is in danger.
[With that, They jumps out the window. Isabella stares after him as the camera slowly pans over to Baljeet and Buford.]
Buford: So, you know, too. It's cool! Um. I mean, I've known first and I've known longer than Baljeet, but it's not a competition...
[Cut to a wide shot of the city with the Berliner Fernsehturm in the foreground. The text "Berlin, Germany" is superimposed over the Beak was flying over a crowd before landing in front of a civilian.]
Phineas: Uh, 'scuse me? Do you know where-
Woman: Nacht Monkey!
[The woman runs away.]
Phineas: No, wait, I didn't...! Aw, man!
[A black Audi pulls up in front of Peter. The window rolls down to reveal Major Monogram.]
Major Monogram: Get in.
[They does so and the car speeds off. Phineas pulls off his mask, breathing heavily.]
Phineas: Mr. Monogram!
Major Monogram: You've got a lot of explaining to do.
Phineas: No, no, no, listen!
Major Monogram: Wait until we're secure.
[He pushes himself back into his seat.]
Phineas: Okay...
[He takes a few deep breaths until Monogram clears his throat. He makes a slashing motion across his chest, indicating for Peter to put his seatbelt on.] Right.
[He tugs on the seatbelt but finds that it's stuck. After a few attempts at loosening it, Peter tugs on the strap so hard that it finally breaks off. Peter nervously looks over to Monogram, who gives him a disappointed look and turns his eyes back to the road. The car pulls into the garage of a very fancy looking building. Cut to the inside of a pristine white facility, teeming with staff members who The Beak and Monogram walk past. O.W.C.A. has obviously recovered from the events of Endgame quite well. The Beak and Monogram enter a conference room where Lyla is standing.]
Major Monogram: So... Is there anything you want to tell us about your girlfriend?
Lyla: He's talking about E.D.I.T.H.
Phineas: Look, I know We made a mistake, and We're sorry, but he is not who you think he is. Khaka peu peu is a liar. Mysterio, the Elementals, it's all fake. He has some sort of illusion tech, and that's how he tricked you guys and he tricked us into giving him E.D.I.T.H. [He pulls out the projector that Isabella recovered and slides it across the table.] It's a projector. I pulled it off the fire monster in Prague.
Major Monogram: So all that death and destruction we witnessed was caused by this?
Phineas: No, not just this! I think he's using drones.
Major Monogram: Well, if this is true, then Mysterio's very dangerous and we need to be smart. Who else did you tell about this?
[Phineas then noticed Ferb is telling him something]
Major Monogram: Boys? Boys!
Lyla: What's wrong?
Phineas: It's Him. He's here.
[He puts his mask back when the hologram starts to disappear, Lyla included. The facility is just an abandoned building.]
Major Monogram: (shocked) What? Lyla?
Phineas: No, it's just an ill...[A missile is fired from behind Him, seemingly hitting and killing Monogram] Monogram!
[He looks back and sees one of the weaponized drones. It takes another shot, blasting The Beak through the back wall, causing him to fall several floors down. Khaka peu peu's voice, amplified, takes center stage. The Beak gets surrounded by drones, all pointing lasers at him]
Khaka peu peu (vo): Wow, Boys. Wow. I thought we were close. Monogram may have been gone. But not you.
Phineas: Show yourself!
[He shoots some metal eggs at one of the drones but misses. Their cloaking devices activate and they disappear, while another illusion gets activated]
Khaka peu peu (vo): I tried to help you walk away. Now you're making me do this… do this… do this…
[Everything goes dark. The Beak, now in the original suit, looks in horror when lights fall down, revealing a school corridor covered in green smoke. Mysterio walks towards him] You told me, you were just ordinary kids.
[The Beak shoots his metal eggs, but only green smoke sprays out of his hands. Mysterio is then suddenly behind him] You told me...[The Beak punches him, only to reveal it's a brick pillar] ...you wanted to run after that girl.
Isabella (vo): Help me!
Phineas: Isabella!
[He runs through a door when he's suddenly on top of the Eiffel Tower. The door breaks loose and falls down. He looks to his right and sees Isabella, confused and scared]
Isabella: Phineas? What's going on?
Phineas: I know this isn't real.
[Mysterio then materializes out of the full moon, grabbing Isabella by her neck]
Khaka peu peu: Do you, though?
Phineas: Isabella! [Mysterio throws her away, He dives after her] No!
[The illusion disappears. Peter hits the floor, Isabella's screams still echoing through his head]
Khaka peu peu (vo): I don't think you know what's real, Phineas... [Echoing] Ferb... Phineas...
[Several buildings pass The Beak at incredible speeds. One of the buildings, with a neon sign that says "Danville" above it, stops before him. Mysterio's gigantic fist then punches through it, sending The Beak flying. He flies through the horizon, it shatters like glass. After falling through some webs, the illusion is briefly lifted] (distorted) You need to WAKE UP! [The Beak crashes on top of a car. He gets back on the ground, looking around, breathing anxiously. A dozen of drones then fly out of the windows of the building, the illusion continues. Huge shards of glass fall down, surrounding The Beak] I mean, look at yourself. [When The Beak reaches out to touch one of his reflections, the reflection comes to life, grabbing his hand. Dozens of The Beaks hurl themselves at Him, pulling his suit away]You are just two scared little kids in a tin can! [The Beaks vanish, Phineas and Ferb is now without suit. He stands among the ruins of a Isabella statue, right in the center of the room.] I created Mysterio to give the world someone to believe in. [The camera focusses on a colossal Mysterio statue] I control the truth! [part of voice lowering down] Mysterio is the truth.
[Mysterio attacks, firing lasers at The Boys. They ducks away and grabs Mysterio. They pulls, only for him to disappear, he had pulled a crane down. They avoids the crane, but not the stone arm that falls on top of him while they screams.] If you were good enough, (softer) maybe you would have prevented the Blip from ever happened.
[A couple of hands bursts out of the ground, trying to grab The Boys, who scurries back in fear. The partially decomposed corpse of Their parents, their friends, and Perry the Platypus crawls out of the grave and . We zoom in on the eye socket, a black widow spider crawls out of it, the eyes transform in several marching Mysterios]
Deep down, you know I'm right.
[Zoom in on one of the eyes on their clothes. It opens and The Boys then finds themselves in a gigantic snow globe, several buildings shoot out of the snow, surrounding him. We zoom out, the snow globe is Mysterio's head, who detaches it from his body] You made your choice, and all you had to do was step aside. And now, you ha-
[Bang! The illusion suddenly vanishes when Khaka peu peu, in his mo-cap outfit, falls on his knees. As he falls to the ground, Major Monogram, who shot Him with a stun gun, limps towards The Beak, who had been lying in a pile of sand. Several operatives drive onto the scene, get out of their cars and surround Beck]
Phineas: (crawling out of the sand) Major Monogram!
Major Monogram: His people... We're trying to find everyone who could expose him. Who'd you tell?
Phineas: Eh...
Major Monogram: I know you told someone. So, just tell me...
Phineas: Okay...
Major Monogram: Boys? (raises his voice) Who else did you tell?!
Phineas: Just our friends Isabella,Baljeet,Buford, and maybe Baljeet told Ginger, but that's it. [Monogram chuckles and shakes his head.] What?
Major Monogram: You... are so gullible.
Phineas: What?
Major Monogram: I mean, you're smart as a whip. Just a... [in Khaka peu peu's voice] ...sucker.
[The last piece of the illusion is lifted, Major Monogram was Khaka peu peu the whole time]
Khaka peu peu: And now all your friends have to die.
Phineas: Oh, my god!
[The two drones on Khaka peu peu's sides project a stream of illusions to scare The Beak away]
Khaka peu peu: It's easy to fool people when they're already fooling themselves. But for what it's worth, Boys... You had this coming.
[The illusion stops. The Boys, confused, gets hit by a train, which drives away into a tunnel]
Khaka peu peu: E.D.I.T.H.?
E.D.I.T.H.: Yes, Sir?
Khaka peu peu: Access files to Phineas and Ferb's class trip. I need them to fly home from London.
[The Beak, dazed and bruised by the impact of the train, climbs on the train's side. He enters it and sits down in one of the seats before they climbing off the suit and sit the other side and they falls unconscious.]
Cut to black.]