(Scene opens up showing the Flynn-Fletcher house.)
Candace: Isn't today great? Today is such a great day! Everything is so great!
Linda: My, Candace, what's got you in such a good mood?
Candace: Jeremy asked me to go play croquet with him in the park!
Lawrence: Okay, well, be sure to be home in time for the barbecue. We're gonna be watching Kermillian's Comet fly past the Earth.
Phineas: A comet? Cool!
Lawrence: It only comes around every seventy three and a half years.
Linda: We'll be barbecuing steaks for the whole neighborhood! Why don't you bring Jeremy?
Candace: You had me at "steaks"!
Phineas: Why is it called Kermillian's Comet, Dad?
Lawrence: Kermillian's Comet was named after an ancient Danville astronomer, Augustus Kermillian, who discovered the comet.
Linda: It's also been said that if you wish on a comet, your wish will come true.
Phineas: Wow! Come on, Ferb. I know what we're gonna do today!
Lawrence: By the way, where is Perry?

Major Monogram: (Talking throughout the Flynn-Fletcher's television set) Agent P, (Perry puts on his fedora) Sorry to disturb you, but we have an emergency. We've just been informed that all steaks in the Tri-State area have disappeared. This has Doofenshmirtz written all over it. Go lay your smack-down on him, Agent P. The fate of the world rests entirely in your hands.
Lawrence: (Walking into the living room) What, the fate of the world?
Major Monogram: Uh, welcome to our telethon. If you're just joining us, your dollars are helping us to find a cure for, um... antidisestablishmentarianism.
Lawrence: Goodness me, that sounds dreadful!
Major Monogram: Oh, it is. It, um, makes you look pale and weak, (He shows Carl) like this young lad.
Lawrence: Oh dear, the poor thing. Look at that. Wait a minute. Antidisestablishmentarianism? That's more of an ideological stance than a disease. Isn't it?
Major Monogram: Uh, well, look at that. (He hides Carl) Seems they just found a cure. Thanks to all the viewers who donated. Bye now.
(Monogram cuts the feed)
Linda: Honey, you ready to go?
Lawrence: Yeah, sure. Hey, did you know they've just found a cure for antidisestablishmentarianism?
Linda: Great. I can finally take off this puce ribbon.

(At the park)
(Song: "Candace (Who's That Girl)")
Jeremy: Hey, Candace.
Candace: Hi, Jeremy!
Jeremy: You remember my little sister Suzy.
Candace: But I thought it was just going to be us.
Jeremy: Well, my folks asked me to keep an eye on Suzy for the afternoon. Who's my favorite girl?
Suzy: I am, I am! (She giggles) Would you show me how to play croquet?
Jeremy: Sure thing, kiddo.
Candace: Is this pie homemade?
Jeremy: Yeah, my Mom made it. I'll go get some plates out of the picnic basket.
Candace:Well, tell her that it's just– (Suzy hits a croquet ball into the pie, shoving it in Candace's face)
Jeremy: Candace, what happened?
Candace: I don't know.
Jeremy: Wait here. I'll go get a towel.
Suzy: So we meet again, Candace Flynn. There's only room for one girl in Jeremy's life, and that is me. And here he comes now. ... Jeremy!
Jeremy: Here's the towel.
Candace: Sorry about the pie, Jeremy. I–I don't know what happened.
Jeremy: Oh, that's okay. You want a soda?
Candace: Yeah, that'd be great.
Suzy: Here, take mine.
Candace: Oh, thank you. That was really– (She opens can and gets sprayed by the soda)
Jeremy: Candace, there's some street performers over there that– I'll go get another towel.

Phineas: These are the blueprints for our giant observatory, Ferb. First thing we need is a lens.
(As Phineas and Ferb build their observatory to the tune of "Quirky Worky Song")
(A laser goes off, and cuts some of Phineas's hair)
Phineas: Cool. Hey, Ferb, new hairdo. Check it out.
(Montage ends)
Isabella: Hey, Phineas. Whatcha doin'?
Phineas: Ferb and I are building a giant observatory to watch Kermillian's Comet tonight.
Isabella: Ooh, that sounds like fun.
Phineas: We're gonna put on a laser light show and, as a grand finale, we're gonna laser our faces into the comet. That way, when it comes back in seventy-three and a half years, we can all show our grandchildren. Oh, yeah, my parents are cooking steaks for everyone.
Isabella: You had me at "our grandchildren."
(A record scratches)
Phineas: What?!
Isabella: STEAKS! You– you had me at "steaks."

(Shopping for steaks)
Linda: Okay, we need to get ten t-bones... No steaks? Oh, dear. Let's try uptown.

Jeremy: So, you wanna see those street performers?
Candace: Sure.
Jeremy: I'm gonna go grab some snacks. I'll meet you over there.
Candace: Okay. Come on, Suzy. Let's go... Suzy? Suzy?
Elderly lady: (Feeding squirrels) Here you go. There's plenty for everyone. (to Suzy) Well, hello there, little girl.
Suzy: Hello. Could I have some nuts to feed the squirrels?
Elderly lady: I'd love to, but I only have one left.
Suzy: (yelling) Gimme the nut!
The lady screams and whimpers as Suzy picks up the nut she dropped in fright)
Suzy: Thank you.
Candace: Suzy? Suzy? Where are you?
(Suzy shows the nuts to two squirrels, then knocks it into Candace's pants)
(Candace screams)

(Song: "S.I.M.P. (Squirrels In My Pants)")
Now somebody, anybody, everybody scream
Candace: Aaaah! There are squirrels in my pants!
Street Performer 1: That girl's got some serious squirrels in her pants.
Candace: There are squirrels in my pants!

Tell me what's makin' you jump like that
S-I-M-P, squirrels in my pants
Ain't got no chickens, ain't got no rats
S-I-M-P, squirrels in my pants.

S to the I to the M to the P
Then maybe you can be movin' like me

Step right over and watch me put it down
Candace: Squirrels! Squirrels!
Step right over and watch me put a...
S to the I to the M to the P

Who ya got back home watering your plants?
S-I-M-P, squirrels in my pants
How can I qualify for government grants?
S-I-M-P, squirrels in my pants

Yeah... Hypnotize me, put me in a trance
S-I-M-P, squirrels in my pants
Get an Aunt Florence living in France...
She can't see the
Candace: Squirrels in my pants!

Step right over and watch me put it down
Candace: Squirrels! Squirrels!
Step right over and watch me put it...
S to the I to the M to the P!

(Candace screams and collapses, and the squirrels exit her pants)
(Candace screams)
Street Performer 1: Wow, she had actual squirrels in her pants.
Street Performer 2: We just got served.

Doofenshmirtz Evil Incorporated!
Doofenshmirtz: One moment, please. ... (Doofenshmirtz comes out wearing two steaks as glasses) Perry the Platypus? What are you looking at? ... Oh, these. Yes, these are my latest invention - steak specs. I came up with the idea after your last little visit. (Doofenshmirtz shows Perry his black eye) With these on, you don't have to constantly hold a piece of steak to your black eye. See? See?... I plan on mass-producing these. I'll make millions. Let me show you. (He shows Perry a containment unit for all the steaks) I've stolen all the steaks in the Tri-State Area, and I keep them here in my steak containment unit or SCU (Pronounced skʰʌ), for short, or maybe it should be SCU (Pronounced skʰu). ... I'm a little on the fence about - Wait. What are you doing? (Perry pulls down a she, revealing an -inator) Oh, that? That's just a giant heat ray in case I want to do something evil later.

Jeremy: Why don't you stay here with Suzy, and I'll go buy you some ice cream?
Candace: No, no, no. You stay here, I'll go buy the ice cream.
(Suzy hits a croquet ball under Candace's feet, making her fall into the ice-cream vendor's cart, and then having that role down a set of stairs)
Street Performer 2: (Watching) Oh, man, we got served again.
Street Performer 1: I'm goin' back to culinary school.
(Candace runs over a mine and crashes into a tree, where a few squirrels fall into the cart with her)
Jeremy: Candace?
Candace: (Returning) Here you go. All they had was fudgie bars.
Jeremy: Candace, what happened?
Candace: There were so many of 'em. The horror, the horror.
Jeremy: Maybe you should sit down. So what happened again?
Suzy: Are you okay? I have something that will make you smile. I want you to meet Mr. Chippy. (pulls a squirrel from behind her back)
(Candace and the squirrel scream at each other)
Candace: Get that sick creature away from me!
Jeremy: Candace, it's okay. It's just a squirrel.
Candace: That's not the one I'm talking about.
(Candace runs away)
Jeremy: What happened to her?
Suzy: (While petting the squirrel) I don't know, but these violent mood swings are probably a sign of deeper emotional imbalance.
Jeremy: What?
Suzy: Heh-heh-heh. Bubbles. Hee-hee.

Phineas: Ladies and gentlemen, welcome to the Observa-Ferb-atory. Step this way, please. Single-file line. The laser show will begin momentarily. Please, no flash photography or cell phones. Thank you. (To Ferb) All right, Ferb, that's everyone. Kill the lights. Space - it's really big. It's filled with planets of all shapes and sizes and millions of shiny stars. Space has also got huge comets soaring through it, including one named after the ancient Danville astronomer Kermillian.
Candace: (Arriving home, and seeing the observatory) What's going on? ... Phineas.
Phineas: And now, behold - Kermillian's Comet. ... Commence laser-engraving sequence.
(The laser engrave's Phineas and Ferb's faces onto the comet)
Candace: Phineas, you guys put your face on a comet? Ooh, I'm telling Mom.
Phineas: Good idea, Candace. She's gonna love it.

Doofenshmirtz: Wait. You're not trying to hack into the ray-gun system, are you? Wait, what am I worried about? You'll never guess my super-secret password.
Heat laser: "Doofalicious". Access granted.
Doofenshmirtz: Okay, that's enough.
(Perry flipps doofenshmirtz onto a large, red button)
Heat laser: Overload.
Doofenshmirtz: (He groans) This should be fun. (The ray-gun begins firing wildly)

Kids: Ooh, wow.
Phineas: Ferb, take it easy with the lasers. Remember, we still got an 8:30 show. Can I have everyone's attention? Please don't panic. We're experiencing technical difficulties. Calmly head towards the exits in a calm, orderly– (A large piece of rubble lands near Phineas) Okay, now you can panic.
(Everyone screams and runs out)
(One final super-charged beam hits the observatory)
Phineas: Ferb, what's happening? (The observatory explodes) That was so cool.
(The crowd cheers)

Doofenshmirtz: (A beam from the heat ray focuses on the Steak Containment Unit) Not the SCU! (Pronounced skʰʌ) Now that I'm looking at the sign, I think it really does look more like SCU (Pronounced skʰu). ... Not the SCU! Come back here! Perry the Platypus, come back. Ooh, something smells delicious. (The top of Doofenshmirtz's building explodes sending steaks flying) Curse you, Perry the Platypus.

Linda: (Arriving home) I can't believe we drove around the whole city and couldn't find one steak.
Candace: Mom, they used a laser to carve their faces in the comet.
Lawrence: Candace, I don't see anything.
Candace: No, no, no.You could only see it from their observatory. Come on, come on. See?
(Candace walks into the backyard and stares deadpanned. Linda and Lawrence walk in as well)
Lawrence: Well, I don't see an observatory.
Linda: Sorry, everyone! We looked all over town, and we couldn't find any steaks.
(Everyone is disappointed)
Buford: Oh, man. I even brought my own plate!
Lawrence: At least we can all enjoy Kermillian's Comet together.
Phineas: Yeah, before it disappears for another seventy three and a half years.
Candace: (runs up to them) Just wait! When I'm eighty-eight, you will be so busted! (runs off)
Ferb: Actually, you'd be eighty-eight and a half.
Candace: (offscreen) Whatever!
Lawrence: So, honey, make a wish.
Linda: I wish we had steaks.
Buford: Yeah, me too.
(Cooked steaks from Doofenshmirtz's SCU begin to fall from the sky)
Linda: I'll be honest. I didn't think that would work.
Baljeet: I did not bring a plate. I thought they would be provided.
Street Performer 2: Dude, we should getting served.
Street Performer 1: Yeah, I'm gettin' used to it.
Jeremy: Candace, are you okay?
Candace: You mean you came over to check on me?
Jeremy: Of course.
(Perry lands on Phineas' plate)
Phineas: Oh, there you are, Perry.

Jeremy: So, that's Kermillian's Comet. Did you make a wish?
Candace: Yes.
Jeremy: And did it come true?
(Candace and Jeremy hold hands)
Candace: It just did.

End Credits

Who ya' got back home watering your plants?
S-I-M-P, squirrels in my pants
How can I qualify for government grants?
S-I-M-P, squirrels in my pants

Hypnotize me, put me in a trance
S-I-M-P, squirrels in my pants
Get an Aunt Florence living in France
She can't see the—
Candace: Squirrels in my pants!

Step right over and watch me put it down
Candace: Squirrels! Squirrels!
Step right over and watch me put it...
S. to the I. to the M. to the P.
Street Performer 1: (On the closing logos) Wow, she had actual squirrels in her pants.