A/N: My unshakable opinion: Phineas and Ferb is the best new cartoon since Camp Lazlo debuted in 2005. And the fact that it's only a few months old and so many fanfictions have already been posted about it just reaffirms this decision.

But, for this oneshot, the newness of the show kind of works against me in not supplying any inkling of when Phineas and Ferb's repective parents married—which isn't helped by the deliberate vagueness about that detail on the show. So I had to improvise, and so tried to write this fanfic just as vaguely, leaving it open to interpretation as to how old the boys where when first they met, as well as what happened to the previous spouses of each parent. So hopefully this story will be mostly immune to any canon revelations that could conceivably contradict it.

Enough exposition. On with the fanfic!

Serendipity

(The Illustrious Crackpot)

Serendipity: noun. "The faculty of finding valuable or agreeable things not sought for."

It sounds trite, doesn't it? Though not a lot of people actively recognize or use the word—well, perhaps with the exception of my brother, who mostly just enjoys the way it sounds—everyone on the planet is constantly "finding valuable or agreeable things not sought for". However, whether or not they recognize these events as such is an entirely different matter. Then again, I suppose that the fact that one might not realize that one has found something serendipitous just fits in with its definition; if one is not looking for it, one won't expect to have found it, even if it is already in one's possession.

And even if one thought one didn't want it in the first place.

It was an ordinary breakfast on an ordinary day when my rather ordinary life was, without any sort of warning, completely upended. Dad was sitting at the table reading The Daily Mail, humming just slightly under his breath, but otherwise acting quite unremarkably normal. So I concentrated my efforts on my meal, having nearly finished when all of a sudden Dad put down the paper and looked straight at me, a kind of grin spreading across his face that I had never seen there before.

"Well, son," he announced brightly, "your father's getting married."

...Utterly shocked, I merely stared at him. And he just continued speaking as though this was just another perfectly ordinary conversation, such as those we regularly had around this same time on other days.

"Yep. She's a wonderful woman—got two kids too, she said. The girl's about four years older than you are, Ferb, but her boy is just a few years your junior. Won't it be great, havin' two new siblings, and a new mum?"

I was absolutely unable to answer. Not that Dad was expecting a reply anyways; he simply began rambling on about this woman, this "Linda", and those two children of hers. It sounded as if he had been bursting to tell me all of this ages before, and at the time I did know that I should have been listening attentively, but...

Mother? Siblings? Where had all this nonsense come from? It would be impossible for me to live with...with anyone besides my father! It had always been just Dad and me, the two of us in our quiet little apartment, mostly attending to our separate matters but still essentially co-dependent. Well, of course Mum—my real mum—was there with us for a time, but it had always been me and Dad. Life couldn't go on any other way. The whole affair was absolutely unthinkable!

But clearly my father had thought of it, because soon enough he did get married, bought a proper house, and "the Fletcher family" somehow miraculously became labeled "the Flynn-Fletcher family". And I was just trying to reconcile myself against all of that when, although my father had never really devoted too much time to "bonding with me", he suddenly seemed not to be paying as much heed to me as he was to his new wife and step-children.

My father had betrayed me, tormented me, and thrown salt on my wounds, and I had had to stand for it. I loathed having to stand for it. And I absolutely abhorred the fact that Dad didn't even seem to notice my complete and utter distaste for our new houseguests.

Though credit was due to "Linda" for attempting to befriend me—treating me on the same level as her other children, asking after my welfare, greeting me with smiles. And I would murmur a cordial reply, not smiling but at least not glaring, and only when I had reached the privacy of my new bedroom could I fully immerse myself in my pent-up emotions, railing malice against the woman whom I blamed for disrupting my family equilibrium.

But even in the sanctity of my bedroom, my tirades were still confined to the inner chambers of my mind and my feelings to the still-deeper realms of my heart. For, lacking sufficient space in the new house for individual bedrooms, I was forced to share mine with the other boy.

Candace, my new stepsister, I did not mind as much as the other members of my new household; she kept to herself as often as she could, on the few occasions when she was actually in the house as opposed to cavorting about with her friends. But the boy...

Phineas, as I soon learned, was far too inquisitive and outgoing for his own good. He was constantly poking his nose—and oh what an enormous nose it was—into other people's business, intruding on conversations where he simply did not belong, and in general disregarding most of the common dogmas of "personal privacy" that other people heeded so well. If ever he encountered a topic that he did not understand, he would ask everyone he met about it, regardless of who they were or what the topic was. If ever there was a closed container before him, he had to open it.

And, apparently, if ever he was presented with an incredibly silent stepbrother, he felt the need to go out of his way to try and make said stepbrother talk to him. Or simply dog that stepbrother's footsteps until such an event occurred.

It was absolutely maddening. Oh, I put up with it for the first few days, imagining foolishly that the phase would pass and I could be left alone once more to wallow in my self-pity. But he absolutely refused to let up. The boy had a tenacity that was unmatched by any other, pursuing me even when I went so far as climbing up onto the roof of the house.

I narrowed my eyes at him, allowing a scowl to slip onto my face in order to better communicate my message. Leave me alone.

He just smiled his bright, innocent little smile and said nothing.

Phineas was always smiling; that was one thing I simply couldn't understand about him. In his eyes, everything was interesting, everything was joyful. Even this—even while pursuing the company of the individual who desired his company the least.

Why couldn't he go off and bother his sister? Or his mother? They were the ones who were actually related to him, after all. The only tie between us was a piece of paper saying that our respective parents were "bound in holy matrimony", whatever one might take that to mean. He had no business with me.

And still he would not let me alone.

When finally I became irritated at repeating the same scene over and over every single day of my life, I decided to change my tactics and simply ignore him. Perhaps it had been the actual act of avoiding him that had attracted young Phineas; after all, that had made his pursuit a sort of an "adventure", a challenge to keep him stimulated no matter how many times he should fail. If I became a more boring conquest, perhaps he would lose his interest and I could be left once more to my own devices.

And so, the next time I caught that flash of tousled red hair from the corner of my eye, I simply grabbed a book, sat down with it, and began to read.

Not that I was at all watching for his reaction, but clearly my choice of a pastime was bemusing to the boy, and for several moments he was at a bit of a loss for what to do. I concentrated wholly on my book, staring so forcefully at the text that the words seemed to be popping off of the pages, attempting to will the boy away by committing myself so intensely to my activity. ...Peculiarly enough, I no longer remember anything about that book except for its blue cover; interesting, those details that our minds retain and those that are discarded.

Soon enough, as I had so dared to fancy, I heard the staccato padding of feet as he left the room—at long last, he had given up! Or so I thought; for I had not even begun to celebrate in earnest when the boy returned, arms encumbered with a large cardboard box, and sat down right next to me.

Absolutely UNSHAKABLE.

Quickly I busied myself with the book again, knees drawn up defensively and head bowed to isolate myself from the world containing this abominably persistent little troll. But an unexpected clatter forced me to peek over the edge of my tome to see Phineas removing from his box little sets of blocks with grooves and holes in them—the kinds that one can connect in a multitude of different ways to form new shapes—and arranging them carefully on the carpet. Quickly I re-concealed myself within my book in an effort to retain my image of indifference...but, not even ten seconds later, I found the book resting unattended in my lap and my eyes riveted on Phineas.

He had a small piece of paper lying on the floor just in front of him, a rough little crayon drawing that depicted what seemed to be a roller coaster track. And, while he was fiddling with these pieces, he would constantly refer back to the paper and readjust the positions of his toys according to what he observed. I watched him struggle with these toys for several minutes, endeavoring to form them in the shape he desired, but devoid of the smallest success. He simply didn't know how to do it, yet still he continued tirelessly with his attempts, never seeming to lose faith in the possibility that it could be done...

After another few moments, I finally rose to my feet, the book slipping carelessly to the floor. The sound alerted the boy, and he looked up just as I bent over him, my face contorted into a slightly irritated expression and my hand outstretched pointedly in his direction.

Give them to me.

Looking somewhat bewildered, Phineas opened his mouth to say something—then, with a start, hurriedly clamped it shut. As much (and as readily) as he would speak with anyone else, he had never spoken directly with me since that day we had first met, when he had discovered that I would not verbally reply to anything he had to say. From then he had made cracking my speech barrier into a game, so that HE was not allowed to speak to ME until I had first spoken to him. Extremely childish, but I preferred his silence to his normal incessant chatter.

I twitched my fingers, growing impatient, and indicated the toys with a curt nod of my head. Give them to me.

The boy seemed a bit doubtful, but reluctantly placed some pieces in my hand. I snapped it closed, sitting back down sharply and, snatching up his diagram, began to work, with Phineas staring curiously over my shoulder. Both hands and mind whirling rapidly, I slipped sticks into grooves and blocks onto other blocks and, with very little conscious effort, I had soon completed a small-scale replica of a roller coaster track. Not exactly like the diagram, perhaps, but completely functional nonetheless.

Phineas let out a hushed, awe-filled breath. He bent over the model, prodding it experimentally, then recoiled swiftly as if frightened that it might fall apart. But it remained upright, and that fact alone caused his face to break into a huge excited smile. Twisting around, he cast the smile on me, barely able to contain his joy—

And, to my utmost surprise, I felt myself smiling as well.

I had always loved building things, anything of any kind that I could get my hands on, be it a model airplane kit or even just a house of playing cards. My father would even bring his power tools to me when they broke down, and I could always repair them, no matter how complex the design. But I had forsaken my art ever since my family had been expanded to include those whom I deemed—...no, not even then. Months before then, I had simply stopped building, formulating silly excuses such as the need to finish reading something or a desire to simply watch television instead.

Phineas gave all of that joy back to me. And even then he was grasping my hands enthusiastically, disregarding his vow of silence in order to babble incoherent praise, and finally scampering back to our bedroom to retrieve more diagrams for me, as well as a few extra armloads of the toys, knowing nothing of what he had done for me than what he could see on my face.

And even then, without any sort of conscious effort, he was also single-handedly solving nearly every problem I had ever faced in my life—loneliness, lack of purpose, a sense of inferiority, a need for understanding. I had never even felt any of those voids until suddenly that boy—my little brother—effortlessly filled them up. In that one instant he became my companion, my leader, recognizing my talents and giving them direction, viewing me as someone important; accepting me, faults and all, without quarrel. In that one instant, he became my friend.

And my life would never have been whole if it had never been disrupted in the first place.

"Hey Ferb," Phineas suddenly begins, blinking at me curiously, "what'cha thinkin' about?"

For a moment I simply stare back at him. Then, to his astonishment, I pull him into a swift but tight embrace.

"...Call it 'serendipity'."