"Up! Get up! Now!"

Harry woke with a start. His aunt rapped on the door again. "Up!" she screeched.
Harry heard her walking toward the kitchen and then the sound of the frying pan being put on the stove. He rolled onto his back and tried to remember the dream he had been having. It had been a very strange and disturbing dream, and longer than any he'd ever –

Harry flung himself upright, and was rewarded for his trouble by banging his head on the underside of the stairs. A spider fell on his lap, shook loose from the ceiling by the impact. He hissed in pain and clamped his hands over the spot he'd hit, his eyes roving around, taking in his surroundings.

He was back in his cupboard under the stairs.

He jumped when Aunt Petunia banged on the door again. "Are you up yet?" she demanded.

"Uhm, give me a minute," said Harry, his head spinning. He'd gone back. He'd actually gone back and was back with the Dursleys in his cupboard and nobody had died yet and he'd gone back!

"Well, get a move on, I want you to look after the bacon. And don't you dare let it burn, I want everything perfect on Duddy's birthday."

Dudley's birthday – he'd gone back to before he'd even known about Hogwarts. A huge grin spread over Harry's face. He'd gone back! Nobody had died yet! He had a chance to fix everything! How was this possible?
Harry's only experience with time travel was their stint with Hermione's TimeTurner in his third year, and back then it had seemed that whatever they did had already happened in the first timeline anyway. It had given him a headache trying to think about it.
A feeling of panic washed over him. What if it was going to be like that again? What if he was forced to go through all those years again, unable to stop anything from happening precisely the way it had before?
Harry's mind spun with questions as he started hunting for his clothes.

When he was dressed, grimacing about having to wear Dudley's cast-offs again, Harry extracted himself from the cupboard under the stairs and looked around the hallway. Everything was just as he remembered it, from the pictures of Dudley that lined the walls to the ugly, mustard-yellow carpet on the floor.
He started when he spotted himself in the mirror. His eleven-year-old self looked even smaller and skinnier than he ever remembered being. Harry studied his thin face, bright green eyes and messy black hair with the scar peeking out from underneath it, then pulled a face at himself and tried to flatten his hair. His Aunt and Uncle had always hated how unruly it looked.

Harry made his way to the kitchen, his mind racing. He'd need to keep his head down until he could figure out what had happened, and what he should do. He went through the well-practiced motions of making and serving breakfast, trying not to roll his eyes at Dudley's temper tantrum when he figured out he'd gotten less presents than last year, and managed to steal some eggs and bacon while the Dursleys were discussing what to do with him during their trip to the zoo after Mrs. Figgs called to inform them of her broken leg.

As Harry sat in the backseat of the car on their way to the zoo, occasionally wincing as Dudley kept poking him in the side, he recalled how elated he had been to finally have a day out, the previous time. The memory made him angry at Dumbledore again. The man had put him with the Dursleys on purpose, never checking up on him or telling them they'd better treat him well, making sure he'd have a horrible childhood. And for what? To teach him some rubbish lesson about – about what exactly? What it is like to be poor and have everyone hate you? What it is like not to have a family that cares for you or to ever feel safe? To condition him never to trust adults so every time something serious went on in Hogwarts, he'd set out on his own rather than warn the teachers?

Harry wandered through the zoo in a gloomy mood, grateful for being ignored by the Dursleys and Dudley's friend Piers. He absent-mindedly thanked Aunt Petunia when she bought him a cheap lemon ice pop, earning himself a glare for being anything less than enraptured by her generosity. By the time they sat down for lunch in the zoo restaurant, he'd made up his mind that this time he would try his hardest not to let Dumbledore decide his course of action. He'd find a way to get rid of Voldemort that would not involve so many people he loved dying. He'd make sure none of them got hurt this time around.

Uncle Vernon looked at him oddly when he waved off the offer of Dudley's rejected knickerbocker glory, but didn't comment.

After lunch they visited the reptile house, and Harry chatted with the boa constrictor for a bit, making sure that neither the Dursleys or Piers Polkiss could see what he was doing. He was relieved to find he was still a Parselmouth. Harry had no idea if everything was exactly the same or some things were different, and if things where the same he'd have a much easier time planning what he had to do.
Still up there, Tom?Harry thought, rubbing his scar with a finger. He'd have to figure out what to do about being a Horcrux as well. Hopefully he could find a method to remove the piece of Voldermort's soul that had latched on to him which didn't involve killing himself.

Harry was allowed a bit of birthday cake when they got back home, even though Dudley had been eyeing his slice, his piggy eyes narrowed. Harry supposed he deserved the cake for not sending Aunt Petunia into shrieking fits and Dudley into a state of near-catatonia by setting a snake on him, and he ate it with relish, making sure to show every bit of enjoyment. He knew it was petty, but it felt good to get back at Dudley after all those years of being bullied by him, even if it was in such a small and insignificant way.

Harry survived the last month of primary school by making a deal with Dudley to do his homework, if Dudley and his cronies left him alone. It wasn't like the homework took him long to do anyway, and not having to stop himself from punching a bunch of eleven-year-olds was a welcome relief. He wasn't entirely sure that would be a good idea anyway, as even though his mind was that of a seventeen-year-old, his body was still that of the skinny, scrawny kid he'd been before reaching puberty. School was a lot more quiet and enjoyable without constantly being hounded by Dudley's gang.
Of course, he couldn't exactly buy off Aunt Petunia with anything, and his free time was still dominated by what she called 'doing chores', but actually was practically running the household for her. Harry had almost forgotten how horribly the Dursleys treated him before they found out he was a wizard (and could scare them off with a simple mention of his ex-convict godfather). He'd been careful not to do too well in school, but still had to endure a shouting match when his grades came back, and they were higher than Dudley's, despite the latter's improvements due to the homework arrangement. Harry resigned himself to being worked like a house elf, verbally abused (even if Dudley had stopped the physical bullying after being promised further help with his homework when he went to Smeltings), and generally being treated as simultaneously a waste of space and a terrible burden.
What he found a whole lot harder to deal with was the hunger. The Dursleys had always seemed to think that every bite that went into Harry's mouth was one stolen from their Dudders. Being hungry and miserable while on the run from wizarding Britain in a tent was one thing when you were a generally well-fed and adequately padded seventeen-year-old. Being hungry and miserable while living with your abusive adoptive parents as an underfed and malnourished eleven-year-old brought on dizzy spells, headaches, and sometimes made Harry's hands shake so bad he almost dropped whatever he was holding. He'd been shocked to realise just how bad his physical condition was compared to the older and decidedly stronger body he'd left behind. He didn't just look weedy, he could be knocked over by a strong gust of wind, and while he was still fast and nimble, his stamina was frankly deplorable.

The summer holidays rolled around, and Harry spent July thinking and planning. Weeding or doing the dishes kept his hands busy, but his mind free to mull over things. He'd discarded the idea that he couldn't alter the timeline after he'd obviously done so on Dudley's birthday, and tried to imagine the effects of any other changes that he'd want to make. He doubted that eating a slice of birthday cake would have any major ramifications, but for instance accidentally-on-purpose getting Ron's rat Scabbers – or Peter Pettigrew, as he now knew – killed as soon as he got his hands on him could have unforeseen consequences. He'd have to be very careful not to alter the timeline in a way that would cause more trouble – and deaths – than he would be trying to prevent.
Harry had considered writing down everything he could remember about what had happened in the seven years between his first days at Hogwarts and being 'killed' by Voldemort, but decided against it as he couldn't risk his notes falling into the hands of the Dursleys, who would surely ship him off to a mental ward if they read them. Instead, he tried to remember everything as clearly as he could, and wondered vaguely where he could read up about creating a Pensieve. One of those would come in really handy now.
In the end, Harry decided that planning out every detail of what he would do would be entirely impossible, as well as useless. While he knew the shape of things to come, he couldn't predict every possible outcome of every action he took that was different from the original timeline. He'd have to try to steer events as they came, and do his best to make sure he was equipped to deal with anything that came up. He identified the four main things he'd need to do: use every opportunity to increase his magical knowledge, get Sirius cleared and elected as his guardian as soon as possible (the thought of his godfather being in Azkaban again made him nauseated), find as many allies that were not direct toadies of Dumbledore as possible (including, Harry thought wryly, media contacts), prevent the restoration of Voldemort's body by all means, and make sure nobodyhe knew got killed this time around.