I dislike vague summaries so here you go:

1) This is NOT a Tom x Harry story. They have a strictly platonic relationship. Neither of them will have a main pairing here, because that's not the focus of this story, although they might become involved with side characters temporarily. Absolutely no bashing.

2) This fic was directly inspired by Notus-Oren's excellent "The Imposter Complex", which I highly recommend, and is similar in many ways. Like in that fic, Tom Riddle here is a very different character from Lord Voldemort, for reasons that will become evident. Be aware that while our stories have similar premises, my Tom Riddle is quite different from his, and will act accordingly.

3) Some chapters contain a little bit of text pulled from Rowling's series, mainly dialogue, as I found that a good way of showing in what ways this story is different from canon and in what ways it is the same. I make no claim to these passages or anything else of J.K. Rowling's.

Right, enough of that!

Tom Riddle wants a new start.

Harry Potter wants a brother.

They both want an adventure.

It all goes downhill from there.

Chapter 1:

The Alley and the Riddle

–HP–

The best day of Harry's life ended the moment he arrived back at Number 4 Privet Drive.

It had taken all of thirty seconds for his uncle to wrench his trunk out of his hands and stuff it into the cupboard under the stairs. Luckily, his owl's cage was too wide to fit through the door; Harry didn't think his uncle would really expected her to stay in there for a whole month, but he was very glad he didn't have the option.

Vernon locked the cupboard door, pocketed the key, and lumbered back into the kitchen.

"We've already eaten," he barked over his shoulder, "so go to bed!"

Harry dragged the birdcage up the stairs and into Dudley's second bedroom with care.

It was full of everything his cousin had broken over the years: A TV set Dudley had put his foot through; a bent air-rifle that Dudley had sat on; a toy plane Dudley had thrown out of the window; and two dozen other things that Dudley's prodigious bulk had manged to mangle in some way.

The only things that weren't misshapen, smashed or ruined were the books, which were in perfe– the book!

Harry clapped a hand to his forehand and quickly dug it out of his pocket. How had he forgotten? His uncle might have locked up his schoolbooks, but he didn't know about the one in Harry's oversized pocket.

It was small, dark, and unassuming – it might not look like it, but it was magical; he was sure of it. After all, he'd found it in a wizarding bookshop hadn't he? Now that he thought about it, it was odd really, that in an entire shop of books on curses, potions, and spells, this little black book had been the only one that felt magical to him.

He had found it in Flourish and Blotts; wanting to avoid the overwhelming crowds and clear his head, which was still swimming with the knowledge that he was famous, he'd wandered off when Hagrid went off to buy his schoolbooks.

Inching around the towering stacks of scrolls, grimoires, and tomes that seemed to hold up the ceiling of the labyrinthine shop, Harry had steadily gotten more and more lost. Somehow he had ended up in a dead-end; a seemingly forgotten corner of the shop, hidden behind a faded purple curtain. It wasn't a particularly exciting section. In fact, compared to the rest of the shop the ancient books left here seemed rather dull.

But there was something about it that made him linger.

Maybe it was the fact that he was clearly the first person to find it in a long while, the floor was dirty enough that he was leaving footprints as he walked – there was a sense of adventure in that – the thrill of exploration. Even if the only thing Harry had found was some very dusty books.

There must be loads of hidden places in the magic world, Harry had thought eagerly, if he managed to find one without even looking for it! Feeling rather more excited than the situation really warranted, Harry peered into every nook and cranny of the dingy space. That was how he had found the book.

Despite having shoved to the back of a shelf, half-hidden in the gloom, he noticed it immediately – it stuck out like a sore thumb.

The tomes surrounding it were massive and heavy and bound with stiff leather. Most of them were large enough to warrant metal clasps; delicate silver ones and thick cast iron ones and a few that shone like gold. Their covers were cracked and stained by time. None of the books looked like they belonged to the same century as Harry.

But instead of thick, brown leather, the book had a thinner, more supple cover of deepest black. It was small enough to fit in Harry's baggy pocket and much too thin to need a clasp of any kind. What had really piqued Harry's curiosity, though, was that it looked like it had been put there very recently.

It lay on a carpet of dust an inch thick, and yet there hadn't been even one speck on it.

But that didn't make any sense, Harry had thought, eyeing his dusty footprints – there were no others. If someone had just put it there, surely there would be some similar sign? Intrigued, he had reached out and grabbed it. As soon as his fingers had brushed the pristine cover, a rush of something had surged up his fingers.

Looking back, he realised it had felt a lot like when he found his wand. Except, while his wand had felt like joy and excitement to Harry, the book had felt . . . inviting. As if the book wanted him to pick it up as much as Harry did.

He'd scrambled backward, and barely had time to read the date '1943' stamped in faded gold letters across the front, when Hagrid had yanked back the curtain, carrying a stack of schoolbooks.

A lifetime of pinching food from the fridge when his aunt had her back turned had instilled Harry with excellent reflexes for exactly this sort of occasion; before Hagrid's eyes had adjusted to the gloom he'd shoved the book deep into the pocket of his tatty jeans.

"Harry," Hagrid said, clapping a massive hand on his shoulder so that Harry's had knees buckled under its weight. "There yeh are, what are yeh doin' back here anyway?"

"Oh, sorry Hagrid," Harry mumbled sheepishly, "I just wandered off a bit."

"Yer a mess!" said Hagrid gruffly. "Come on now, we gotta get yer cauldron."

They were halfway down the street before Harry realised that he hadn't bought the book, and as guilty as he had felt at stealing – even if it was an accident – he had been too embarrassed to admit his mistake to Hagrid. And for some reason, he didn't want to share his discovery with someone else, even Hagrid, who had been so nice to him.

Instead, he decided he would leave some extra money there when he next went to the bookstore, and keep it a secret.

Now that Harry was back at Number 4 Privet Drive – which felt painfully boring compared to the wonders of Diagon Alley – he finally had a chance to look through it. He studied its front cover; it was black as tar and despite its age looked to be in good condition. On the back cover was the address for a newsagent's on Vauxhall Road, London.

How strange, thought Harry, for a Muggle book to be so far from anything even slightly Muggle-ish. Maybe it was a disguise, in case it fell into the wrong hands?

He decided that was probably the answer; in truth, he just couldn't wait any longer. Excitedly, he opened the book to the first page.

'Diary of T. M. Riddle' was written in tall, cursive handwriting in the middle of the yellowish page, underlined with an elegant loop. A diary – it was a wizard's diary!

He turned the page again, eager to read anything about magic that he could get his hands on.

It was blank. Utterly blank.

Despair seized Harry, and he flicked through the rest of the book at lightning speed. The rest of the pages were exactly the same, blank, except for a small date in the top left of each page. He couldn't believe it.

He was so sure he felt something in Flourish and Blotts – that this book was special in some way.

Harry suddenly felt very foolish; it was just some stupid normal diary. No wonder it had been left in the dust and the dark.

Tossing it onto the ground, he turned off the light and fell backward onto the bed. The exhausting day had taken its toll on him. Harry couldn't believe that he'd woken up in a leaky shack out in the sea this morning, it felt like a lifetime had passed since then, and now he had a lifetime's worth of things to think about.

His mind didn't seem to know what to focus on: how he had apparently destroyed the Dark Lord Voldemort; the murder of his parents; Diagon Alley and Gringotts; going to Hogwarts and leaving the Dursleys; the disappointing diary; the list went on endlessly, and it took him a very long time to fall asleep.

–HP–

Harry's next few days with the Dursleys wasn't fun. True, Dudley was now so scared of Harry he wouldn't stay in the same room, and Aunt Petunia and Uncle Vernon didn't shut Harry in his cupboard, but that was probably only because he wouldn't fit with the trunk already in there.

Half terrified, half furious, they acted as though any chair with Harry in it were empty – until they needed something from him. Although this was an improvement in many ways, it did become a bit depressing after a while.

And his list of chores was just as endless as ever, and while watching his aunt try to communicate them to him without actually speaking was funny at first, soon it just made him even lonelier.

Now that he knew that there was an entire secret world waiting for him to come and join it the Dursleys were more unbearable than ever – he had never felt so unwanted. So Harry kept to his new room, with his new owl for company. Rather brilliantly, he thought, he'd had the idea to name her after a famous witch.

The only problem was, he didn't know the names of any famous witches, so he resolved to look through his History of Magic book as soon as he could.

Mostly, he lay on his bed and read Dudley's discarded adventure books late into the night, his owl swooping in and out of the open window as she pleased. It was lucky that Aunt Petunia didn't come in to vacuum anymore because she kept bringing back dead mice.

Every night before he went to sleep, Harry ticked off another day on the piece of paper he had pinned to the wall, counting down to September the first.

With little to do, Harry found himself spending an unusual amount of time staring at Riddle's book. Even though he knew it was blank, he kept absentmindedly picking it up and turning the pages, as though it were a story he wanted to finish.

And while Harry was sure he had never heard the name T. M. Riddle before, it still seemed to mean something to him, almost as though Riddle was a friend he'd had when he was very small, and had half-forgotten.

But that was absurd. He'd never had friends before, Dudley had made sure of that.

Late one night, feeling tired but unable to sleep, Harry took to throwing pens and pencils from his bed, trying to land them in the pot on the desk. It was difficult and most of them missed, some rather spectacularly; like the felt-tip pen he managed to throw out of the window and into his aunt's prized flower bed.

It took one of them bouncing off the radiator and landing on top of Riddle's book for inspiration to strike. What if the book wasn't blank, but was just hiding its contents? What if he needed to show the book that he was a wizard?

That would explain why it looked so normal. Surely, he thought excitedly, if he could just prove he wasn't a Muggle then it would reveal its true contents to him!

He leapt out of the bed so quickly that his foot got tangled in the blankets; he fell to the floor with a thud.

Heart in his mouth, Harry stayed very still and quiet. His aunt and uncle might not want to so much as look at him recently, but he was pretty sure that waking them up in the middle of the night was a pretty good way to get thrown back in his cupboard.

When the deep rumbles of Vernon's stores didn't change, he got back up carefully and turned on the frilly lamp on his desk. Snatching up the pen and book, he flipped to the first blank page and paused. What could he say to prove he was a wizard? He decided to start small and work up to it.

"Hello, my name is Harry Potter."

The words lay there, looking perfectly ordinary, for just a moment. Then they soaked into the page like water into cracked soil.

Harry gasped loudly, staring at the book as he marveled at the simple display of magic. Before he could think what to say next black ink bubbled out of nowhere onto the page; it pooled and twisted to form the same precise, slender handwriting that the book was signed in.

"Hello, Harry Potter. My name is Tom Riddle. How did you come by my diary?"

The words faded in the same manner as Harry's, but he was already scribbling a response.

"From Flourish and Blotts, the bookshop on Diagon Alley, when I went to get my books for Hogwarts. Do you know how it got there?"

He waited eagerly for Riddle's reply.

"I cannot be certain, but I suspect it was stolen. It's lucky that I recorded my memories in some more subtle way than ink. But I always knew that there would be those who would covet this diary."

"What do you mean?" Harry scrawled, excited that his hunch had been correct – this book was special!

"I mean that this diary holds powerful knowledge. Knowledge that those in power wanted to cover up. Knowledge that you will not find within Hogwarts School of Witchcraft and Wizardry."

"I'll be going there in three weeks." Harry wrote quickly. "What sort of knowledge are you talking about?"

Harry's heart was hammering in his chest. None of Dudley's adventure books were even half as thrilling as this.

"Magic, of course. I know more about the deepest corners of magic than wizards thrice my age. When I was a student of Hogwarts, just like you, I sought for magic that they told me was a legend, that they told me didn't exist. But they lied. I uncovered secrets and spells that I was not supposed to find, and they forbade me from ever telling the truth. They gave me a nice, shiny trophy for my trouble and warned me to keep my mouth shut. But I knew that what I had discovered was too important to remain hidden – it had to be taught to others. So I made this diary; so that I one day I could pass on what I knew to a worthy successor."

Harry couldn't believe his luck – he'd thought he would have to wait until he got to Hogwarts to learn more about witchcraft and wizardry. The way Riddle was writing, magic sounded mysterious and complex. He had so much more to learn than he had first thought, he realised.

And Hagrid had told that everyone knew Hogwarts was the best wizarding school in the world, he bet all of the other students knew loads of magic already!

Panic suddenly took hold of him – a terrible vision of him being turned away from Hogwarts and being sent back to the Dursleys.

"Can you teach me?" he scrawled hurriedly.

Harry chewed the end of the biro worriedly, waiting for a response. If Riddle agreed to teach him, surely there was no way he could be turned away from Hogwarts – he was clearly a brilliant wizard.

"I'm not sure about that. I don't anything about you except your name; how do I know I can trust you?"

"I won't tell anyone anything, I promise." Harry wrote. "My family hates magic anyway, they're scared enough of the word – I don't think they could handle me telling them actual spells and stuff."

Riddle seemed to be thinking things over; he was taking a long time to respond. Harry was just starting to think he might not ever when finally new words formed on the page.

"That's reassuring, Harry. Very well, I will consider your request. But I'll need some time to decide; I still don't know anything about you – you are complete stranger to me. If I knew you better it would help me make up my mind."

A wide grin spread Harry's face. That was a good start.

"What do you want to know?" he asked.

Riddle's reply emerged from the page slowly – contentedly. The writing wasn't as tall or sharp as his previous messages. Harry thought it looked . . . friendlier. He took it as a good sign.

"Let's start small and work our way up. Why don't you tell me about your day?"

–HP–

Tom Riddle was doing some serious thinking.

He'd gotten very good at it – years of existing in the dark void of the diary had given him a great deal of practice. It had been a necessity: either think or go mad.

The child had stopped writing to him halfway through a sentence; presumably, he'd fallen asleep. Now, at last, Tom was free to think through the implications of everything he'd learned, which was admittedly not very much.

At least the boy had been laughably easy to manipulate. Most witches and wizards – even children – were wary of enchanted books at the best of times, and the Diary he was residing in was toeing the line of being cursed.

But the boy as Muggle-born it seemed, if the comments on his family were true, which was mixed news for Tom.

On the one hand, he'd been blissfully unaware of the danger he was in and had practically handed himself to Tom on a silver plate. It also meant there was almost no chance of an actually competent wizard finding the diary for several weeks. Only once the boy took him to Hogwarts would he be in any real danger of discovery.

That bought him crucial time to investigate what had happened out in the Real during his long isolation and form a plan of action.

On the other hand, Tom thought irritably, it would severely handicap his planning because it meant the boy likely knew essentially nothing of the wizarding world, let alone its history.

Still, he could work with what he had been given.

Tom had given his well-honed speech; designed to enthrall whoever came across the diary – to make them want to keep it secret and safe. It had worked perfectly, and if he had a mouth with which to smile, he would have.

A convincing display of caution and the boy was falling over himself to prove to Tom that he was worthy – as if Tom was actually going to impart anything valuable to some snot-nosed child. Despite how much he wanted to, Tom refrained from asking anything beyond the inane; specifically, questions about his Real-self, and instead simply laid down the groundwork for future interactions.

Tom had languished in that diary for an eternity, he was patient and willing to wait. And as he waited, he did what he'd been doing for most of his life.

There was nothing physical in the Unreal, nothing with which he could occupy himself; the only thing he had was his mind and he was not the sort of person to let it fall into madness without a fight.

Yet, despite the sharpness of his mind, he felt woefully blunt as he tried to wrestle what he knew into some sort of coherent sequence of events. Tom knew a complete picture was far off, but he could begin trying to surmise answers to the most important questions.

Firstly, how had a child, on their first trip into Diagon Alley, managed to come across his Horcrux?

The diary was supposed to be kept on his Real-self's person at all times, not left in the busiest place in Wizarding Britain. After all, it was much more than just an anchor to the mortal plane.

Tom had acted as a sounding board for his Real-self; they had spent countless hours deliberating and honing plans. He had always had an excellent memory, but the diary could recall anything ever written into it, which made it invaluable as a store of knowledge.

He was sure his Real-self would not have simply cast it aside carelessly; even after they had begun to argue his Real-self had continued to use the diary as pseudo-grimoire for years – it was just too useful.

As he continued to ruminate, Tom only became more anxious.

He'd gotten the year out of the boy, 1992. Unless something had gone seriously wrong, his Real-self would be in a high position of power by now. He tried to reassure himself that even if he were the Minister of Magic right now, it wasn't that unlikely that a Muggle-born wouldn't recognize the name, or make the connection.

'Tried' was the operative word, because it wasn't working. There were just too many niggling problems – a dozen little questions that dragged the pacifying scenario through the mud. Even if Muggle-born might not recognise a famous wizard's name, surely the curators of Flourish and Blotts would? Wouldn't they return it to its rightful owner?

Cataloguing that line of thinking for later, Tom continued. How had he ended up in the well-known bookstore?

He admitted to himself that it wasn't entirely unlikely that his Real-self had decided was no longer important enough to carry around – they had been steadily splitting apart over the years, disagreeing more often and more vehemently. Furthermore, the very reason they had created multiple Horcruxes was that it made each of them less of a vulnerability.

And, Tom thought bitterly, thus less valuable to his Real-self.

Yet still, if his Real-self had decided to hide the diary somewhere permanently, he would have concealed the diary away somewhere dark and deep, like the cave he'd visited in his youth. Diagon Alley was about as far from dark and deep as it was possible to be.

Had his fictitious speech actually been correct, had the diary been stolen?

It seemed unlikely; the diary was very unassuming to look at. Not to mention, not many people would be able to steal from Tom Riddle and get away with it. But if his Real-self had been unable to do anything about it – if he had been killed, then maybe it wasn't so unlikely.

He would be able to come back, of course, he knew the ritual intimately, but Horcruxes were among the most obscure Dark Magic in the world; it wasn't exactly a well-studied field. Tom had no idea how arduous the process would actually be in practice. That theory certainly held merit, he thought grimly.

Then Tom's metaphysical heart skipped a beat; what if something had gone wrong with the rituals? He had gone further down the path to immortality than any other wizard in history, of that he was sure. Was it such a leap to think that he might have failed in some unforeseeable manner?

Tom and his Real-self had agreed that more than one Horcrux was essential for true security from death. They had theorized, based on Herpo the Foul's speculations, that splitting the soul too many times would result in a cascading failure of every piece – it would simply be too unstable.

So they had gone over the arithmancy a thousand times – designed and discarded a hundred rituals – searching for that elusive stability. But it had paid off; Tom was sure that a seven-part soul with every piece carefully linked together by a ritual only he was brilliant enough to dream up would have afforded his Real-self true, sustainable immortality.

But what if his Real-self hadn't been able to reach that number, and that was why he hadn't written to Tom in decades? What if he'd fractured at five or six? Was Tom's existence in the diary serving a purpose, or was he an anchor for a broken soul that had shattered beyond repair?

Harry slept on soundly, albeit in an uncomfortable position, utterly unaware of the terror racing through the book his head rested on.

For Tom, it was a very, very long night.

–HP–

Harry woke up with a start. There was a sharp rapping noise coming from the hallway; his aunt was knocking on the door.

"I'm up, I'm up!" he called.

Harry heard her walking toward the kitchen and then the sound of the frying pan being put on the stove. Picking his head up from the desk, he flushed; he'd drooled a little bit on Riddle's diary during the night.

He blinked the sleep from his eyes and debated writing to him – he should probably apologise for falling asleep midway through their conversation. It would have to wait though, because he could hear his uncle's massive footsteps getting closer.

Harry stumbled over to the door and managed to open it before his uncle woke up half the street with his hammering. Vernon was standing in the hall, one meaty fist raised to do just that.

He gave Harry a look of deepest loathing – probably upset he didn't get to savage the door, Harry thought – before turning and lumbering downstairs, with Harry in tow.

Aunt Petunia was cooking bacon in the kitchen, but as soon as Harry walked in she snapped her fingers at him and sat down at the table. With a sigh, Harry took over the cooking.

He had finished the bacon, sausages, and toast and had moved on to frying half a dozen eggs by the time Dudley arrived.

Breakfast was as tense and uncomfortable that morning as it had been since Harry's birthday. His uncle hid behind his newspaper, Dudley ate as fast as he possibly could – a speed that would have been impressive if it weren't so disgusting – and Aunt Petunia alternated between glaring at him angrily and pretending there were only three people at the table.

After Vernon had left for work and Dudley had left to terrorize the neighborhood, Petunia told Harry his long list of chores for the day. While his cousin lolled around watching TV and eating ice cream, Harry cleaned the windows, washed the car, mowed the lawn, trimmed the flowerbeds, pruned and watered the roses, and repainted the garden bench. The sun blazed overhead the entire time, burning the back of his neck.

Wish they could see famous Harry Potter now, he thought savagely, as he spread manure on the flower beds, his back aching, sweat running down his face.

It was half-past seven in the evening when at last, exhausted, he heard Aunt Petunia calling him. He gladly moved into the shade of the gleaming kitchen. There were two slices of bread and a lump of cheese waiting for him on the kitchen table; he washed his hands, bolted down his pitiful supper, and ran upstairs as fast as he could.

His owl had come back at some point and was now snoozing in her cage. Harry quietly pulled out the rickety chair and sat down, picking up the biro. He wondered how to start the conversation.

–HP–

"Good evening, Mr Riddle. Sorry I fell asleep last night."

So the boy had finally decided to write to him again. Tom didn't exactly have a clock to hand, but he was pretty sure he'd been left alone in the void for longer than one night. Still, appearances had to be maintained, he thought.

"That's quite alright, Harry, and please – call me Tom." He replied, though he felt a prickle of irritation at the informality.

"Ok, Tom. Is there anything you want to talk about?"

He sneered inwardly; the boy had written to him, not the other way around! Luckily for him, there were a great many things Tom wanted to talk about. He'd start with the most natural-sounding one.

"Yes, I was wondering," Tom wrote, "when you found me in Flourish and Blotts, was that your first time in Diagon Alley?"

"Yeah, it was. I didn't even know magic was real until Hagrid told me," the boy replied.

Hagrid? Surely not the same Hagrid he'd gotten expelled creating this very diary?

"I imagine it was an enormous shock, seeing the magical world for the first time. I've not heard of a Hagrid before, does he work for Hogwarts?"

"He's the groundskeeper and Keeper of Keys. You must have gone to Hogwarts before he started working there, you would definitely remember him. He's nearly nine-foot-tall!"

So it was the same Hagrid then; it wasn't like there were many half-giants frolicking around Britain. How on Earth had that oaf winded up working at Hogwarts?

"And you're right, it was a huge shock! I didn't even know I was famous, my aunt and uncle never told me about magic, or my parents, or You-Know-Who."

Well, that was an unexpected twist, Tom thought. What would an eleven-year-old be famous for? And how was he supposed to know who You-Know-Who was?

"You must be right, I don't know anyone like that. I'm afraid I don't know who you are talking about either, or why you are famous," he wrote, barely containing his irritation.

"Really? Everyone knows the story apparently, except no one told me. You-Know-Who was a Dark wizard – the most powerful of all time. Hagrid said only Dumbledore wasn't afraid of him. He killed my parents when I was a baby, but he couldn't kill me. Hagrid said he didn't die exactly, but he lost his powers and is too weak to keep fighting. Everyone at the Leaky Cauldron recognized me, but I don't even remember what happened."

Tom's metaphysical eyebrows climbed higher and higher with each word. A baby defeating a Dark wizard? That was certainly a first, but he'd read of magic doing strange things before. It seemed to have a will of its own at times.

Of course, it was possible the boy was just lying, but Tom didn't think so.

If he was trying to impress Tom, claiming he'd done something astonishing as a baby was a very strange way of going about it. Still, if he was lying, Tom would find out easily enough. Most children were terrible liars and sooner or later he'd slip up.

"That's certainly an incredible feat, Harry," Tom wrote. "May I ask why you call this Dark wizard 'You-Know-Who'?"

"Oh, Hagrid said I shouldn't say the name because people are still scared of him." How pathetic, Tom thought. "But his real name was Lord Voldemort."

And just like that a wave of darkest dread consumed Tom, as he was instantly cast back decades to a conversation he'd had with his Real-self – a conversation about changing their Muggle name to something more commanding.

It suddenly all clicked into place with a terrifying finality: the most powerful of all time . . . didn't die exactly . . . only Dumbledore wasn't afraid of him. . .

Tom was vaguely away that he hadn't replied to Harry and hastened to correct his lapse.

"I should thank you for destroying him; he sounds like a fearsome wizard."

And he really did, Tom thoughts with horror.

How had his Real-self become so terrifying that more than a decade after his destruction adults were still afraid to say his name? What in Merlin's name had happened since they parted ways?

"Yeah, he must have been. I think I'm going to go to sleep now. Good night Tom."

He barely registered the words.

"Good night Harry."

–HP–