Summary: When Perry won't allow them to come with him on a mission, Phineas and Ferb decide to go on their own mission. When an old enemy kidnaps Isabella, the boys see this an opportunity to prove that they can handle it.

This episode is really long. Enjoy!

Mission: Improbable

*Backyard*

Phineas and Ferb were going at it, barely avoiding punches and kicks from one another.

(This brief tune is a parody of Platypus Fight from the PnF episode, "Doofapus.")

Fight, fight,

There's a step-brother fight!

It's a fracas, it's a fray,

It's a family melee!

Linda immediately took notice from the kitchen. "What in the world!?" Paternal instincts taking over, she zoomed outside and pulled her sons apart from each other. "What is going on out here?"

Perry was leaning coolly against the tree. "It's okay, Linda. They're just sparring."

"Yeah," Phineas confirmed. "Perry's been teaching us some moves."

"We're throwing punches and kicks near each other," Ferb added, "not at each other."

Linda relaxed, but was uncertain about this new information. "Uh, Perry, is this a good idea?"

Perry crossed his arms, slightly offended. "Hey, a guy's gotta be able to defend himself. We can't protect those two forever, you know."

Linda rolled her eyes and sighed. "Don't remind me. Alright. Just be careful."

"We will," Phineas assured, as his mother headed back inside. He grinned at Ferb and assumed a fighting stance. Ferb did the same. "Put 'em up, Ferbooch. The more we practice, the sooner Perry'll let us come on a mission with him."

Perry started at that. "Whoa, whoa. Who said anything about a mission?"

He walked up them, as Phineas said, "Once we get good enough at fighting, we can be partners in fighting crime, right?"

Perry narrowed his eyes. "Wrong." Phineas frowned, and both the boys dropped their stances. "I'm sorry, boys, but it's too dangerous."

"But-" Realization struck Phineas. "Oh, you're worried that your boss will find out that we know you're a secret agent."

"That's only part of the reason." Perry's wrist-comm beeped. "Boys, we're gonna have to cut this session short." He lifted up a section of the lawn. "I'll see you after work." He dropped down the opening *Perry*, and the lifted section dropped back down over it.

After staring longingly for a moment, Phineas said dejectedly, "I can't believe Perry won't let us help him. I get that his boss can't find out that we know about O.W.C.A., but it's almost as if Perry doesn't think we can handle a mission." An idea came into his head, and he smiled. "Ferb, I know what we're do, today." He put his arm around Ferb's shoulders. "We're gonna become spies, and prove to Perry that we can do his job just as good as he can." Phineas looked up at nothing, like people do in sit-coms, and Ferb did the same. "Look up, and picture it, Ferb. Us on our own secret mission..."

Ferb pictured it and liked what he saw.

(This song a parody of the opening theme to the Jimmy Neutron, Boy Genius episode, "Operation: Rescue Jet Fusion.")

Phineas and Ferb... (The boys are wearing tuxedos and fedoras. The camera zooms in on them from behind. They turn around, and their names appear beside them.)

They're the spies who are a bit young for what they do...(The boys use suction cups to scale the side of a building and reach the roof.)

Phineas and Ferb... (Ferb whips out a small laser, and Phineas nods.)

Their gadgets are better than mine. (Ferb uses the laser to blast a hole into the roof.)

And, how about this song...? (The boys jump down the hole and use small parachutes to land safely in the dark room.)

Phineas and Ferb... (Isabella is tied up in the back, and the room is filled with the ninja-vampires from the PnF episode, "Nerds of a Feather.")

Nothing can bring them down. (The boys assume fight-stances.)

And, no girl can resist their charm. (Isabella looks upon the boys admiringly.)

One's triangular, (For the next few lines, the boys fight the ninja-vampires.)

One is shaped like an F.

But, they will never fail!

Phineas and Ferb... (The boys head for Isabella and untie her.)

They are spy guys! (Isabella hugs Phineas, and he hugs back.)

They are spy guys... (Isabella them gazes into Ferb's eyes, wraps her arms around him, and kisses him on the lips, and he wraps his arms around her and kisses back.)

"Do you like what you're picturing, Ferb?" Phineas asked. "I can't see it, but I bet it's awesome."

Ferb had to agree, but there was one problem. "It is awesome, Phineas, but how can you be sure that we'll become spies, today?"

Phineas frowned. "What do you mean?"

"We can't just make something happen. That would be cheating."

Phineas face-palmed in frustration. "Oh, duh. You're right, Ferb. It could be weeks before something happens."

*Unknown Location*

Isabella slowly opened her eyes. After a moment, she assessed her situation. She was tied to a chair, there was duck-tape over her mouth, and she seemed to be in a basement. The door opened, and someone she never thought she'd see again stepped into the room.

*Bedroom*

Ferb picked a sheet of paper up off his bed and looked it over, not liking what it said.

"Whatcha got there, Ferb?" Phineas asked. Ferb handed the paper over, and Phineas read it aloud. "The Beak, it's been a long a time. I'm sure you recall all the times you've thwarted me. Now is the time I have concocted my revenge, thank you very much. I have your friend, Isabella. If you ever want to see her again, you will come to 123 Gopher Road at precisely eight PM tonight. And, do not bring the Beak suit. Signed, Kha Kha Peu Peu." (The Beak) Phineas tore up the paper in anger. "I can't believe it! Seriously, we haven't even been The Beak in, like, two years! It looks like we really are gonna be spies, Ferb. I just wish it was for a different reason."

*Kha Kha Peu Peu's Basement*

Isabella glared daggers. "Phineas and Ferb'll put you in your place. You'll see!"

Kha Kha Peu Peu laughed. "Without the Beak suit, they'll be powerless to stop me, thank you very much."

"Dude, they haven't been The Beak in, like, two years."

"Well, I'm still upset!"

Kha Kha Peu Peu flinched at his wife call of, "Harold! Are you concocting revenge, again?"

"No, honey," he lied. He braced himself, then relaxed. "Huh. I was certain she'd-" a chair knocked him over, "-throw a chair at me."

*Living Room*

Phineas and Ferb were wearing tuxedos and fedoras. They tip-toed down the stairs, praying that they wouldn't attract attention. They looked around the room. The coast was clear.

"Come on, Ferb," Phineas whispered. The raced quietly to the door. "We don't want Perry to know-"

Perry appeared directly in front of the door, arms crossed and gaze more curious than suspicious. "Don't want Perry to know what?"

Phineas came to an abrupt halt, and Ferb bumped into him from behind. "Oh, th-there you are, Perry," Phineas said as casually as he could, which wasn't very casual at all. "We were just...o-on our way to...visit Stacy! Yeah, that's what we're doing!"

Perry nodded, though he could tell Phineas was lying. "Uh-huh. So, why didn't you want me to know about it?"

"A-an excellent question, Perry!" Phineas scratched his ear anxiously. "We didn't want you to know because...we're planning a surprise party for your birthday!"

"My birthday isn't for another four months."

Oops. In his haste, Phineas had forgotten about that. "Better early than on time?"

"Okay, so why do you look like O.W.C.A. agents in tuxedos?"

"It's a...formal-secret-agent-themed party."

"I see." Perry pulled out his cellphone. "Well, why don't I just call Stacy, right now, and confirm that?"

Phineas gulped. "Y-you don't have to do that."

Perry raised an eyebrow. "Why not? It's not like you're lying to me, are you?"

"Um..."

Deciding that he'd seen enough, Ferb threw a ball on the ground, and white smoke filled the room. Perry coughed as the smoke lifted. The boys were gone, further raising the platypus's suspicions.

"Well, that happened," Perry commented. He looked up in confusion. "How did the smoke detector not catch that?"

*Gopher Road*

Phineas and Ferb crouched in the bushes across the street from Kha Kha Peu Peu's house.

Phineas sighed suddenly. "I can't believe we lied to Perry, of all people. Or, animals." Ferb put his hand on his brother's shoulder. "I know, Ferb. He would have tried to stop us, if he knew what we were doing." Phineas's eyes narrowed in determination. "But, we have to save Isabella ourselves. Move out, Agent F."

Ferb saluted, and he and Phineas crossed the street to their enemy's house. They crawled to the side of the house. Phineas asked, "Agent F, man the cute-tracker ('The Chronicles of Meap,' 'Meap Me in St. Louis'). What's the reading on the victim's location?"

Ferb pulled the cute-tracker out of his tuxedo. He looked at it and said, "She's in the basement, Agent P."

To Phineas's surprise, Ferb whipped out two shovels and handed him one. "Shovels? We're using things as un-spy-like as shovels?" Ferb pushed a red button on the shovel, and it turned into a small drill. "I stand corrected."

They drilled underground, eventually startling Isabella by popping up out of the ground and into the basement. She was utterly relieved to see them. She tried to express this, but due to the duck-tape, the only thing that came out was, "Mmmmm!"

Phineas was the first to notice her as he and his brother climbed out of the hole. "Isabella! Are you okay?"

Isabella nodded. Ferb pulled the duck-tape off her mouth. It hurt, but Isabella was glad he did it. Her eyes shown with admiration for them. "I knew you guys would save me!" The door opened and closed. Isabella gasped. "Kha Kha Peu Peu!"

The boys turned around. There he was. The Beak's old nemesis.

Kha Kha Peu Peu was mildly surprised that Phineas and Ferb had arrived so soon. He gave a cocky smirk. "Well, well. If it isn't The Beak themselves." He frowned. "You know, sometimes being early can be just as rude as being late, thank you very much."

Phineas and Ferb assumed battle-stances, as Phineas demanded, "What's your game, Kha Kha Peu Peu?"

Kha Kha Peu Peu smirked again. "An excellent question. You see, kids, I've been out of the game for a while to please my wife. But, I've decided, to heck with her! If she doesn't like me being evil, then I don't give a crabapple, thank you very much!" He paused, waiting. "Wow. I can't believe she didn't hear that." He narrowly avoided a chair that flew across the room. "Nevermind. As I was saying, I can't be evil with you two around, so I've lured you here to eliminate...your memory of ever being The Beak! I'd eliminate you two, but I'm not evil enough to do that. Especially to children, thank you very much." Kha Kha Peu Peu frowned in confusion. "By the way, what's with the tuxedos and fedoras?"

"I was wondering about that," Isabella added.

"It always helps to look cool," Ferb stated.

Kha Kha Peu Peu shrugged. "Whatever. Now, unfortunately, you kids came here before I could finish making a memory-erasing device." He grinned. "But, that doesn't really matter."

Phineas shot a warning glance at Ferb. "Get ready, Agent F. He's gonna try something." Two ropes fell frown the ceiling and wrapped themselves around the boys. "Wow. I thought he would do something more intense than this."

"It was the best I could do on short notice, thank you very much." He was suddenly tackled by Phineas, who began twisting the man's arm painfully. Ferb stood nearby. "How did you two get out of those ropes?" He glanced at ropes, which were tied around wooden versions of the brothers, each one labeled, 'Decoy.' "Decoys? That doesn't even make any sense." (Backyard Aquarium)

Phineas told Ferb. "I'll untie Isabella." He headed off-screen.

Kha Kha Peu Peu stood up. "Oh, you're gonna pay for- Wait, I can't beat up children."

Ferb jumped on his face and punched him. Ferb then kicked him in the chest and jumped off, as Kha Kha Peu Peu flew across the room and landed in a pile of boxes.

Isabella stared at Ferb in amazement. "I am so in love with him, right now."

Phineas, who had just finished untying the ropes, just looked at her. "What?"

"Nothing."

Kha Kha Peu Peu stood up. Phineas and Ferb looked at each other and nodded. They both lunged at him. Phineas had him in a headlock, while Ferb was bending the man's leg back painfully.

Isabella stared for a moment, not sure who she was more in love with. She shook her head clear and pulled out her cellphone. "I'm calling the police." With a triumphant smirk, she said, "Kha Kha Peu Peu, you should have taken my phone, when you had the chance."

*Living Room*

Phineas and Ferb headed inside, feeling proud of themselves. "Did you record all that, Ferb?" Phineas asked. Ferb took one of the buttons off his tuxedo and held it up. Phineas pumped his fist. "Yes! Spy-cams are awesome!"

Perry snatched. "They sure are."

Phineas grinned smugly. "Well, well, well. It's nice to see you, Agent P."

Perry was feeling just as smug. "Once I see what's on this, you two will be so busted." He frowned. "Did I just say that? I think Candace is rubbing off on me."

*Bedroom*

Perry uploaded the video to the computer. Phineas and Ferb stood behind him, wondering how he'd react.

"Let's see what you boys have been hiding from me," Perry said as he pressed play.

Phineas and Ferb watched their friend intently, studying his reaction. His first expression was one of surprise, then worry, then finally pride. Phineas and Ferb smiled at each other.

They did not expect Perry to hop off the chair and angrily say, "What's the matter with you two? Do you know how much danger you've put yourselves into? How could you go on a rescue mission and not invite me!? You could have at least told me about it!"

Phineas stomped his foot in frustration. "That's just it, Perry! We couldn't tell you, because we knew you'd try to stop us! We're not babies anymore-"

"You're still my little boys!" That shut Phineas up. Perry let out a breath. "Look, I do want to team up with you guys. I-I just don't like idea of you two being out in field, like that. You both did really well, and I wanna stress how proud I am, but it still scares me. You got lucky this time, but what about next time? I wouldn't be able to live with myself, knowing that you two got hurt - or worse - and I wasn't there to prevent it."

Phineas and Ferb exchanged guilty looks. Phineas said, "We didn't think of that. We're really sorry, Perry."

Perry shook his head and smiled slightly. "No, don't be sorry, kid. You two saved Isabella and put Kha Kha Peu Peu in prison. Like I said, I'm proud of you guys, and I want to partner up with you. Which, I can do."

Phineas gasped in delight, and Ferb grinned. Phineas asked hopefully, "Y-you mean we can finally work with you?"

Perry sheepishly rubbed the back of his neck. "Well, I have been working on something..."

Phineas started bouncing, barely able to contain his excitement. "Show us, show us, show us!"

Perry chuckled, struck by how young Phineas and Ferb were. These two can bounce from mature to childish in the blink of an eye, Perry thought. Well, mostly Phineas.

*Backyard*

"Remember The Beak's old lair?" Perry asked as he and his boys walked up to the tree.

"What about it?" Phineas asked.

Perry pressed down on a section of the tree. A light briefly shown under his hand. A large section of the tree opened up. "The scanner only responds to mine and you boys' hand prints. Come on."

He stepped into the opening, and his boys did the same. The opening closed, and the three of them rode the elevator up to a room. The lights automatically turned on. So far the only things in the room, besides some boxes, were a computer, a desk, and a chair.

"This-this used to be The Beak's hideout," Phineas noted.

Perry smiled. "I know I should have asked before I started redecorating, but I wanted this to be a surprise. You see, boys, I've always known that you two would be a big help on missions. I just didn't want to risk putting you in danger, so, after you two told me you knew I was a secret agent, I starting my brain for ways you could help out and still stay safe. Then, it hit me; you'd be great with the technical aspect of a mission. I've already cleared it with your parents and sister, so if you'll accept this compromise, it would be my honor to call you my mission specialists. What do you say?" Phineas was squealing like Isabella in the episode, 'It's No Picnic.' Perry frowned. "Phineas, are you okay?"

Phineas slapped himself. "This-this is..." Phineas pulled Perry into a hug that was way too tight. "This is amazing!"

"Can't...breathe..." Perry choked out. Phineas let go of him, and Perry smiled, when Ferb pulled him into a much gentler embrace. "Obviously, it's not finished, yet, but-"

Ferb let go of Perry, and Phineas felt ready to burst from excitement. "Ferb, we're officially on the team! I'm so happy! I don't know what to do!" He ran around in a circle. "Someone tell me what to do!" Barely able to contain his laughter at such childish behavior, Perry tripped Phineas with his tail. "Thanks." Phineas stood up.

"Let me just be clear on one thing," Perry stated. "Since this is tied into the O.W.C.A., you cannot tell anyone about it." Phineas and Ferb put on serious expressions and saluted. Perry laughed. He jokingly wagged his finger at them. "Are you making fun of me?"

Phineas and Ferb said simultaneously, "Yes. Yes, we are."

Perry laughed again and shook his head.

**Credits**

(This song is a parody of Perry the Teenage Girl from the PnF episode, "Does This Duckbill Make Me Look Fat?")

-Female Singer-

They're American and British step-brothers of action.

Doo-be-doo-be-doo-ba,

Doo-be-doo-be-doo-ba.

They're a secret agent's partners, and will never flinch from a fray-ay-ay.

You best leave them alone.

They're busy inventing at their home.

And, whenever they're around, you can hear the bad guys say...

-Kha Kha Peu Peu-

Aren't they a little young to be mission specialists?

-Female Singer-

They're Phineas!

Phineas and Ferb!

The End

Phineas and Ferb are working with Perry now! Review to see what happens next!