[a/n]I do like reading time travel stories, but the involvement of a grown [sometimes old] man with kids… could you really stand it? Going back to 12 from 20 or 50 or 100? So a different take on changing history.

[a/n2] This got such a reception as a 1shot, it's going out on its own. Harry changing history just by letting Young Harry know what's coming.

Harry Goes Back

The ancient Headmaster of Hogwarts looked over his work. The work of decades. It had taken everything he had ever learned in his long life. Runes, Arithmancy, Potions. Dark Arts, too, like Necromancy. He'd also violated many laws, the least of which would earn him a decade in Azkaban. But, now, the project was ready. It was too late for him to be stopped now. He would right the wrongs, or at least give himself the ability to do it better.

"Professor Potter! Unspeakables!" came through the office door "We know what you're planning! Surrender!"

In response, Harry scratched his thin pate of scraggly white hair and replied "Good morning, Miss Creevey. It's always a pleasure to welcome old students. Do come in. Please."

"It doesn't have to end badly, Headmaster." A curly redhead youth brandishing a wand, said.

Making no effort to go for his wand, he merely smiled "Ah….young Percival. So like your namesake. Quoting rules. One day you will learn some things transcend the law."

"We cannot allow you to change the past." Said a middle-aged wizard with pink hair and a blue mustache.

Again, the old wizard was only pleased "It is my past to change, Remus. And I am not doing it just for myself. If it works, your grandfather will grow up with his parents instead of stories."

"You don't know that Granpa Harry." There was nothing of law enforcement in Teddy's grandson's voice, at this point, himself a grandfather. Only that of family "You could change one event and cause a ripple effect that will destroy everything. What if it backfires? You won, isn't that enough?"

Harry dismissed the objections "No, it's not. First, you go by the Monument of Victory every day. Shortening that long list of names of Death Eater murders is my only concern. Second, I have been working on this longer than you have been alive, child. I assure you, I've accounted for every possible twist."

"Enough of this!" exclaimed Percival "Put down your wand. Step around your desk SLOWLY! And hold your hands high."

The Headmaster sighed, looking defeated and appeared to comply, then he said "Now Fawkes!" The phoenix let out a high pitched screech and all the Unspeakables collapsed. "Well done, old friend. Goodbye Remmy. Fawkes, you know I'm not coming back."

The Unspeakables watched while the old Headmaster called on all of his powers. He drew a circle in front of him. The noise was piercing, like something was ripping a hole in the universe. Which was basically accurate, Diagon Alley was visible in the circle, but a Diagon Alley of LONG AGO. They watched him pick up a large and still overstuffed packing envelope and walk through. They had failed their mission.

Abcij

"It worked!" the old man grinned. Then promptly collapsed. This is where Necromancy came in. Time travel to this extent simply could not be survived. Runes carved all over his body glowed through all the colors of the rainbow, and after a few minutes, he stood on very shaky legs. His wand became a cane to hold him up. Not quite sure where he'd landed, he asked a passerby "Tom's Bar?"

The repulsive, dirty man answered "Find your own way." The old man looked an easy mark, so he reached into the robes with practiced ease. And his hand promptly fell off.

"Best watch that, scum." Old Harry sneered. And realized "Knockturn Alley." He walked through to Diagon Alley to buy the property for his plan.

A week later he was ready and in the Leaky Caldron. He grinned as he watched his [Merlin! Was he really that small once?] his younger self open the door. This was perfect. But Hagrid came first, approaching with a smile he said "Hello, old friend."

"Hi there." Hagrid replied, holding the obviously aged man's hand gingerly "Sorry, I don recognize ya."

"A friend of the old crowd. I've been waiting for Harry to appear. It's good to see you again, been too long." Old Harry said. Then he smiled at the boy "Hello, Harry, I owe a debt to your family. There's a package in here and a letter explaining it. It was nice seeing you."

Young Harry looked up, wondering about this old man, who somehow seemed familiar "Have I ever met you before, sir?" he asked, curiously.

"I stayed with your parents during the war." Answered Old Harry "Hagrid will tell you all about Voldemort?"

Young Harry asked "Why don't you come with us?" Eager to hear about his parents.

"I'm sorry I don't have much time here." Said Old Harry "You see. I'm going away."

Young Harry asked "When will you be back?"

"No, Harry. I mean that I am about to die." Answered Old Harry.

Young Harry sighed "Oh. I'm sorry.

"Don't be, Harry. I'm a very old man. I came here knowing I would die. Self serving though it is I wish you a long life and a happier one." Old Harry told him with an unconcerned smile "Good bye, Harry … Rubeus."

Young Harry didn't understand what the old man meant about self serving. And at just eleven he really could not imagine being ready to die. "Well, goodbye then. Sir. And I'm still sorry."

"I didna get yer name." said Hagrid.

Old Harry answered "James Evans." Smiling with amusement at the semi-truth he shook his younger self's hand gravely.

Abcij

Old Harry hadn't missed the mark on his estimate of his death. During his preparations, he'd got around mostly by premade Portkeys. The time travel spellwork had drained his magical core beyond recovery. He'd known it would. And knew he would die soon after his task was complete. The Knight Bus was prompt and he greeted them "Hi Stan. Hi Ern. Manchester please. It's under family wards so I'll direct you when you're close."

"Take it away Ern!" said Stan.

The Shrunken Head ordered "Yeah! Take her away Ern!"

"That'll be 5 Galleons 6 Sickles 11 Knuts Guv'nur." Stan tipped his hat to the old man.

Harry gave a tired smile "You know, Stan, I got all my business done a bit underbudget, I have ….errrrr…. 416 Galleons … hmm imagine that! 6 Sickles 11 Knuts. You three have fun, knock off early." His heart gave out during the first sharp right turn.

Abcij

"Wonder what the old man gave me." Young Harry wondered.

Vernon demanded "What was that, Potter? IF you want to disturb my driving, you'll bloody well make sure I can hear what you say."

"Just thinking about some of the reading I have to do before school, Uncle Vernon." Harry felt like it was a lie, but didn't really care.

Vernon found that amusing "Hhahahah" he boomed "Now that I can get behind! Homework all the time! Keep you freaks out of trouble.".

"Big behind." Harry muttered, sarcastically. But the rest of the ride proceeded in silence. He rushed up the stairs and opened his trunk and pulled out the package from the old man. Opened it. Inside was a pocket-sized book and an envelope with a letter inside. He picked up the book and opened it, but it only had one page inside.

No Cheating Harry Read The Letter First

"Smartass book" Harry snorted. He tossed it onto the bed he had in Dudley's second bedroom. Then he obeyed.

Hi there Harry Potter

Sorry about the little book bomb. Well. Not really. I'm entitled. I've been at this longer than your Headmaster has been alive. I'll leave you to ponder that until you meet him. Ready for a surprise? One as big as Hagrid?

Harry raised a skeptical eyebrow.

Well, I'm the guy who gave you this real large package. No, that's NOT the surprise. The surprise is that my name is Harry James Potter. That's right, I am you. I was born July 31, 1980 just like you. My parents were killed October 31,1981. My first memory is of wrestling with a big black something you can't quite remember. My first memory of Uncle Vernon is dislocating my shoulder. I had spiders named Pafoo and Moey I shared the Cupboard with. And I was the best short order cook 10 or under. That should convince you I'm for real.

Harry was amazed. No one could know so much about him. Things he barely remembered.

I'll fill in the animal memories when the time comes. That brings me to the book. It is a diary. That isn't a dirty word. And it's the most important book you will ever own. DO NOT EVER LOSE IT! SLEEP WITH IT! TAKE IT IN THE SHOWER WITH YOU! It has all my memories in it. It tells you everything up to the moment you entered the Leaky Cauldron with Hagrid. You'll actually learn about my last days first. The book is especially charmed, magic not taught in Hogwarts. Because this will come up next year, it is NOT LIKE TOM RIDDLE'S DIARY. Why did I do this?

Good Question, Harry thought

I was a war hero, Harry. I had a long and successful life. You saw an old man, Bloody! To you 40 is old. I give you permission to tell Vernon I said that.

Harry giggled in the silent way he'd learned to do.

What I never really had, my young self, is true happiness. People died who should not have. No. I couldn't go back to save Mum and Dad. The book will explain when you know enough to understand. I wasted time and energy on people who weren't worth it. Trusted people I shouldn't have. Didn't stand up or speak out for myself. The course you were on before now would be the same as me.

Harry considered that. Could he get the Dursleys to stop abusing him?

You have a war to fight and friends and family to save. The ultimate goal is to kill more of them than they kill of you. How am I going to get you there? With properly timed explanations of what's happening and why. Who to trust and not and why. General advice is another way. The first general bit is that you will stop performing down to Dudley's level. Study and learn. The Dursleys won't care about your Hogwarts grades. You'll be able to compare report cards with me and I hope you outperform me from First Term. The plan is to get you doing Seventh Year work before your Fourth, and more of the right subjects.

Harry thought that good advice, admitting he might not have changed his study habits.

Next is physical, you're a scrawny little wog right now. The Dursleys, of course. Potions to properly fix all those old injuries and effects of malnutrition. You'll always be thin, but we're going to put on muscle. You'll curse me for weeks but the sooner you get exercising, the better.

Harry frowned. Wha? Him? Exercise? Yuck!

I apologize in advance. As I learned more and more about my life, I had to deal with betrayals and manipulative adults. As I created our diary, I realized I had a major problem. The book would eventually be useless. So I decided that some events need to happen without any advance warning from the book, while others I could explain in advance. This will seem just like manipulation to you, and you'd be right. But I had to strike a balance between improving our life and telling you about something bad that has to happen for something good later. An example will occur very soon, I won't give you many details about something bad that occurs on Halloween.

Harry scowled at that. He immediately didn't like being told about something he could prevent if he knew enough. At least the letter was admitting it.

You could,….if you want… destroy the diary. The only effect my little time trip will have is the Healing Potions, see Madam Pomfrey, exercise and school work. Study! The diary is spelled so only you can read it, but better safe than sorry. Run it through the shredder and cast an Incendio on the cuttings. In a couple minutes, the diary will start to glow, that means new pages are there available to read. So, Harry? What's it to be? Potentially big good change, and big risk, I admit? Or no diary, not much change? It's your life and your decision; make it a good one.

Good luck Harry

Harry James Potter 82nd Headmaster of Hogwarts

Young Harry reread the letter…again….and again…thought about it…read it another time. And finally decided.

The book was glowing.