I do not own Harry Potter.
The day before going to DoM Harry has overheard his 'friends' and McGonnagal discussing his 'visions'. He had learned that Dumbledore was planning his demise and due to Snape spying he knew that Voldemort will send Harry false vision of Sirius being tortured to lure him into DoM. They wanted Sirius to join the rescue team and die during the fight, this would allow Harry to inherit the Black estate. In his next year Harry would die fighting Voldemort, fulfilling some sort of prophecy and passing the whole wealth to Dumbledore, Longbottoms and Wesleys. Hermione would get the Potter and Black libraries.
Next day during DoM fight Harry didn't bother stunning people, the result was eleven Death Eaters dead, some minor injuries among his 'friends' and a chance to hear The Prophecy. After the fight ended he was brought to the Dumbledore's office along with all the conspirators.
"Harry, you have killed eleven people, don't you feel any guilt?" This couldn't continue. Thought Dumbledore. If Harry fights like that he will kill to many Tom's followers. So many purebloods will die and without them Wizarding World might be overrun by muggleborns and destroyed by those silly ideas like equality or tek-no-logi.
"I have put eleven rabid animals down, that's the difference." Harry was angry. Dumbledore tried some Leglimency but didn't get anything, possibly due to all the anger and emotions.
"They were people, they made mistakes. You should capture them and let them atone for those mistakes in prison." Secondary argument of Dumbledore.
"Voldemort would bust them out of prison in a week, that is assuming they would even get there. Malfoy bought his freedom once, he could do it again." This time Harry was almost shouting while saying it.
"This doesn't mean you can kill them. Everyone deserves a second chance, even them." Primary argument of Dumbledore, Harry was a bit surprised that Dumbledore has reversed their order, usually it went 'they deserve a second chance' and later 'they can atone and change'.
"Everyone proffer?" Answer to this question will decide how Harry will leave this place. Dumbledore still didn't notice where this was going.
"Yes, everyone my boy." YES YES YES! Harry was shouting in his mind, they took bait, hook, line and sinker. That idiot Dumbledore didn't know that his insistence on giving people second chances will be his downfall.
"You are right professor."
"Even murde..." Dumbledore stopped, he didn't expect Harry to agree and was already going through his prepare speech. "I'm happy you understand that, my boy."
"I decided I don't want to be like them. I cannot change the past and help people who died by my hand but definitely I can change the future." Things were going quite well, Harry renounced killing. Dumbledore didn't suspect that killing some Death Eater would cause so much guilt in the boy.
"Thus I decided I won't be fighting Voldemort again."
People gathered in Dumbledore's office were speechless. Boy-Who-Lived, The Chosen One, Wizarding Savior etc. decided to stop fighting against You-Know-Who? After a moment of silence everyone started shouting at him, Dumbledore decided to wait and avoid general shouting.
"Harry, but you are the Chosen one, how can you stop fighting against Him?" Dumbledore hoped Harry was joking and Hermione's words would end this cruel joke.
"Potter, I always knew that! You are a coward, without me and Granger you would be nothing!" Weasley like always didn't help. Dumbledore often wondered if Weasleys didn't somehow found a way to affect the Sorting Hat, there was no other way to explain how they ended up in Gryffindor.
"Potter, just like your father, some problems and you are immediately running away. I could have expected that." Severus... Dumbledore wasn't even surprised here, Severus had magnificent ability to ignore everything that didn't fit into his small world, like James Potter trying to stop Voldemort without his wand to give his wife time to escape.
"Mister Potter, how can you say that, You-Know-Who killed your parents, how can you allow him to get away with that?" Ah, Minevra's guilt trip, she has beaten him to it.
"Harry... I never suspected, son of Prongs, a coward? I.." Lupin only shake his head. Another guilt trip, Dumbledore himself couldn't do this better than that.
"Harry, how can you do such thing? You will leave us on that monster's mercy?" This time guilt trip done by Ginevra, Dumbledore knew very well that Weasleys are pureblood supremacists as much as Malfoys. They just lacked money to be considered a 'proper' family and due to that they were banned from pureblood social circles. Thus their decision to join 'light side' which wasn't that much different from the 'dark' side. They did not like killing muggleborns (someone had to do all those petty jobs that no pureblood would take) or slaughtering muggles (they are such silly creatures, did you know that they believe that one of them went to the Moon?).
"Harry, how can you say such things! You are a disgrace as a Gryffindor." Neville joined the discussion with a typical Gryffindor bravado. Good thing that Dumbledore removed all good history books about the Founders (and pretty much about anything else other than goblin rebellions) and maintained idea of Gryffindors being noble heroes going into action without any kind of plan. This was completely false when it came to Godric, he was a master tactician and strategist that employed underhand moves more often than not. Dumbledore found out that it was because some Chinese book written by Son Zu, or something like that (that book, like any other written by muggles, was banned in the wizarding world, a law made by Dumbledore of course).
Harry raised his hands to silence everyone and give him chance to speak.
"Listen, I know you think I'm coward and that I'm abandoning you." Harry tried to calmly explain.
"What? You aren't?" Ronald cut in only to be silenced by Hermione.
"It's just I agree with Headmaster that Voldemort like everyone else deserves a second chance. Due to the Prophecy if I fight him I might kill him and prevent him from having a chance to redeem himself." Dumbledore didn't expect that, Harry made everyone speechless twice in last five minutes. Now, there is still chance to salvage this situation, he needs to work fast before his own ploy is turned against him.
"Harry, my boy, I understand your reluctance, but you have to think about other people, Voldemort will kill hundreds if not thousands people if left not opposed." Guilt trip number nine.
"Professor, you said it yourself EVERYONE deserves a second chance. Besides I only said that I won't fight him, I won't stop you from opposing Voldemort." Dumbledore looked at his minions, they were agreeing with Harry! He trained his followers so good that when they hear 'he deserves a second chance' they immediately agree. Even Weasley would now notice if he changed his crown argument about redemption and second chances, so it was time for plan B – The Prophecy.
"I understand that, but you know about Prophecy, you are the only one that can stop him."
"I'm sure professor that Voldemort will see the error of his way after slaughtering countless innocent people." Dumbledore couldn't counter that as he was planning to use exactly same argument at some point regarding the Death Eaters Harry killed.
"Harry, what about your parents? Will you allow their deaths to go unpunished?" Dumbledore tried yet another approach.
"Seeking a revenge is a bit dark and I don't want to become a dark wizard like Voldemort. I'm also quite sure that with your help professor The Ministry will be able to capture Voldemort and give him a fair trail where he will be punished for my parents deaths." And another attempt shot down, everyone knew that revenge was 'dark', so Dumbledore being Leader of The Light convincing Harry Potter to seek it would not work.
"What about your friends Harry? Many of them will be in danger during incoming moths."
"They can stay at Hogwarts for the summer, it's the safest place in Britain." And now this was going to bite Dumbledore in the ass. At some point Hogwarts had been the safest place in Britain. Last time wards were upgraded about 70 years after introduction of the Statue of Secrecy. It was enough time for all muggles knowing about this place to die from an old age. Without threat from the muggles the Board and Ministry didn't wish to spend money on ward upgrades. Last century saw even cuts in the maintenance to the point where a dozen average Death Eaters would overload wards without much problems. Now Hogwart relied on it's reputation of 'best warded place in Britain' which served as well as a replacement for wards for the past two centuries.
The problem was Dumbledore had little to no arguments against that, but...
"What about their families?"
"Everyone can notify their families about problems in our world thus allowing them to move, without magical children around those families will be just another muggles, I doubt that Death Eaters know how to find someone using muggle means, they have never found me by simply using phone book." Unfortunate truth, only reason Harry wasn't attacked by Death Eaters for all those years was that while they did learn his address at some point, they didn't know how to use muggle maps to find him. Fortunately no one ever came up with an idea to send him a letter and follow the owl...
"What about muggles? Voldemort will target them."
"It's ministry's duty to deal with that, I'm neither an Auror nor a Hit Wizard. And if Voldemort will kill to many muggles then their military will step in and deal with the threat." Muggles getting involved in wizards matters won't be good, their military was numerous and had very destructive weapons like cannons or rifles. Dumbledore even heard that muggles were creating cannon that could shoot as much bullets as hundred rifleman, fortunately such thing was supposed to be very large and expensive so the muggle military couldn't have too many of them.
Before Dumbledore could answer Harry continued.
"Listen, I know you want me to kill Voldemort, but after what professor said about killing I don't think I can do that. By killing him I would lover myself to his level and I don't want to be same type of person as Voldemort." Dumbledore was defeated, if he pushed Harry and said it's OK to kill Voldemort Harry would want to kill his followers as well. Saying 'no' to that would end in argument 'how many murders are required for a person to loose their second chance' and Dumbledore knew it won't end well for him. Maybe it was better to forfeit this battle and return to it in September? Yes, he could use Severus to orchestrate death of Hermione Granger to give Harry reasons for a revenge. Dumbledore didn't like the idea of giving away Potter and Black library but that stupid girl wasn't interested in money. Thus Dumbledore simply sat and watched as Harry left the office.
As soon as Harry was far enough to not be heard he grabbed small bracelet, quietly said "Activate" and disappeared from Hogwarts.
Harry appeared on small muggle yacht somewhere on the ocean. It was quite easy to evade all Portkey detectors, they only show if traffic had occurred not it's destination so if someone portkeyed to target outside detection range, say middle of theAtlantic ocean, no one would be any wiser. Even if the Ministry or Dumbledore had any means to locate the Portkey target it still wouldn't help them as the yacht on which Harry has landed was under the Fidelius Charm.
Back at Hogwarts Dumbledore felt someone leaving the castle by a Portkey. For a moment he panicked that it could be Harry but he reminded himself that the boy neither is not capable of creating portkeys nor he has anyone to help him so it was probably someone from Slytherin who has learned about death of their parent and wanted to go home to mourn.
"How did it go pup?" Asked very alive and very happy Sirius Black.
"Dumbledore gave me his 'second chance' speech, I gave him mine."
"You told them that Voldemort deserves a second chance?" Sirius almost didn't believe him. Almost, this was Harry Potter after all.
"Yup, they didn't notice but after hearing that they stayed speechless for over four minutes, yes I did count time."
"So what do we do now?"
"I always wanted to travel around the world." Said Harry.
"Fine by me."
"By the way, thanks for that anti-leglimency potion. Dumbledore tried something but apparently his attempt has failed."
"Harry, without it we would never be able to do half of the stuff we did. And did I mention how proud I am of you?"
"Why? Because I managed to get away?"
"No, because you managed to prank Dumbledore, Voldemort and the Ministry." Sirius said grinning.
With Harry Potter gone from Hogwarts a mass exodus of muggleborns and half-bloods ocured. Before start of the next school year more than half of the Magical Britain population has left, Voldemort simply walked into the Ministry and declared himself a Supreme Ruler. He tried attacking the muggle world but when RAF bombed several mansions of some prominent Death Eaters Voldemort decided that annoying muggles might not be his best idea. His plans to invade the mainland Europe failed spectacularly when he noticed that due to his pureblood only policy his forces were outnumbered more than five to one. After a single battle Voldemort lost most of his army and went back to Britain to lick his wounds. He was destroyed ten years later by a new Dark Lady.
Dumbledore died while defending Hogwarts, he was ressurected several months later in his secret lair. He tried to rebuild his power under a new name but his attempt was unsuccessful. His greatest achievement was becoming the Minister of Magic in France, he was kicked out after his first term due to some unpopular reforms he tried to pass. He lasted five years longer than Voldemort but a new Dark Lady got him too.
Ginny, Ron and Neville died during the siege of Hogwarts.
Hermione Granger completed her education in Australia, she then started research and developed an improved version of horcruxes. The improvement had left the user sane after creating one. With the new knowledge Hermione took over the magical world, it was very easy for someone with common sense and... guns. She killed both Voldemort and Dumbledore but after twenty years of ruling she got bored and faked her own death.
Harry traveled the world for several years. When he got bored he settled down in Australia where he met Hermione. It was a shock for him to learn that Hermione was planning to betray Dumbledore from the moment he forced her to work with him, she couldn't tell Harry that because Dumbledore or Snape could read his thoughts. This was the reason she was so bitchy about Harry learning Occlumency from Snape. She was a bit 'annoyed' when Harry told her about a potion developed by his mother. The new crater on the Moon had nothing to do with that... They married couple years later and had three kids. The youngest one wanted to be a hero so they faked a grand battle between Dark Lady Granger and young Heroine Lily Notgranger. Wizards never noticed the similarity in both names and appearances.
Lily Notgranger lasted an entire decade before becoming another Dark Lady, this has won her parents a right to say 'I told you so' for another century.