A/N: I realise people dis coving Perry's secret life as an agent is a little cliche, but this is my first P&F story, so I'm just getting to know my way around writing with these characters. Please, enjoy.
Perry had managed to wriggle out of the newspaper, and was currently fighting Doofenshmirtz. The Acknowledge-the-Loser-Inator had already been destroyed, and was now only a smouldering pile of debris from an explosion.
Isabella, Baljeet and. Buford found themselves outside an apartment door, after the chair came up through the door. On the door read Doofenshmirtz.
"Let's see who lives here," Isabella said, knocking on the door.
"Not now, I'm busy!" Doofenshmirtz exclaimed from inside, as a knock was heard at the door. There was another knock. "Go away!" They heard the sound of a door opening, and the three kids stared at the sight of a platypus and a strange man with a pointy nose fighting on the floor. They froze at the sight of the three kids who suddenly appeared. Doofenshmirtz, obviously, didn't know who the kids were, but Perry recognised them, and quickly pulled off his fedora to hide his secret identity.
"Who are you kids?" Doofenshmirtz asked. He looked at the platypus standing on his chest.
"And who is this little platypus? What happened to Perry the Platypus?"
"That must be Doofenshmirtz," Isabella said. "Oh, there you are, Perry." Perry chirped.
"Oh, isn't that cute. He has the same name as my nemesis. Anyway, kids, I'm very busy today. I have to clean up this mess." He gestured to the building around them. Things had been destroyed in the fight, and the Acknowledge-the-Loser-Inator had blown a huge hole in the wall as well.
"We can help you!" Isabella said. "I still have to earn my Clean-a-Random-Stranger's-House Patch."
"Oh, you must be one of those adorable I little Fireside Girls," Doofenshmirtz said. "I think I've seen you around with your little troop. You're all so cu-" He was cut off from a swift kick to the jaw from a platypus in a fedora. "Perry the Platypus! Where did you go? And what happened to that cute little platypus with the same name as you?" The kids just stared, and Perry rolled his eyes at Doofenshmirtz ignorance.
"Perry!" Isabella cried, rushing up to the platypus. "I can't believe it! You're a secret agent!"
"Oh, I get it!" Doofenshmirtz exclaimed from his place on the floor. "You kids are new recruits for the O.W.C.A.!" Isabella raised an eyebrow at him.
"No..." she said slowly. "No, we're not."
"I do not even know what that means!" Baljeet exclaimed.
"Our Wombats Crunch Apples?" Buford suggested.
"What? That does not make any sense!"
"That's what you said about Perry being a secret agent, and looky right there!" Buford pointed towards the platypus in the fedora, who had a guilty look on his face. He glanced apologetically at Doofenshmirtz, who shrugged.
"You kiddies said you were going to help us clean my house?" he said.
"Well, our work here is done," Isabella said, as she admired the work of her and her friends. "Nice to meet you, Dr. Doofenshmirtz. You, too, Agent P." She shook both their hands/paws. "Now we can finally tell Phineas and Ferb where their pet platypus goes."
Perry's eyes went wide, and his face turned slightly pale. He was just about to stop them, when Doofenshmirtz activated another trap. Perry chirped in defeat, and glared at his nemesis from his place in the cage.
"Don't worry, Perry the Platypus, you're little secret is only getting out, and the whole world will soon know, and you'd have to be relocated. Or better yet, taken out of the agency, so that I, Doctor Heinz Doofenshmirtz, can take over the entire TRI-STATE AREA!" That's when Perry bent the bars to escape, and attacked Doofenshmirtz.
A/N: Please review!