DISCLAIMER: Harry Potter belongs to J.K. Rowling, who isn't me. The only profit I get from this is personal satisfaction.
Miscalculation
George went to detention alone. He walked slowly, so as to enjoy the nostalgia of being at Hogwarts before the remodel that was necessary after the Battle of Hogwarts. He passed by the staff room and heard voices.
"Where did Dumbledore go this time? The Ministry?"
"No. He only mentioned it once and kind of mumbled it, but I think it was some kind of shack."
"The Shrieking Shack?"
"No, I think it started with a G."
No, George thought. He opened the door to find Trelawney and Sinistra talking. "Was it Gaunt Shack, by any chance?"
"That's it!" Trelawney declared. George bolted out of the room. Dumbledore has gone to kill himself. Why didn't I warn him about the dangers of Gaunt's Ring? I am such an idiot!
"Expecto Patronum!" he shouted. Dumbledore, do not touch the resurrection stone or the ring it's on. If you haven't, send your Patronus back to George Weasley. If I don't get word from you, I'll assume the worst and bring Severus to you.
He wasted no time in searching for the resident Dark Arts expert and found Snape patrolling the corridors.
"Why in such a hurry—" Snape started to ask.
"No time!" George said. "Do you have basilisk venom?"
"I keep a little, but—"
"Accio! Snape, if there's anything you need to fight off a nasty dark curse from a ring, get it now. Do you know where Gaunt Shack is?"
"No."
George swore under his breath. Where could we find out where to go? The Pensieve! Whatever-his-name-Gaunt's memory should still be in there! "Meet me in Dumbledore's office. If you dawdle, he'll die."
Snape understood and flew towards his stores and hopefully grabbed the basilisk venom that George summoned on the way. George, with his body's short legs, ran as fast as he could to the Headmaster's office.
"Mr. Weasley!" McGonagall said just as George arrived at the gargoyle. "You are supposed to be in detention!"
"I need to get into Dumbledore's office right now."
"He's not here—"
"I know that!" George snapped. "He went off to Gaunt Shack and he's going to get himself killed."
"Calm down—" McGonagall said.
"Time is of the essence," Snape said as he came down the corridor to the gargoyle. "Gummy bears. Move it, Weasley."
"Severus, I—"
"Trust my judgment, Minerva." Snape and George ran up the stairs to Dumbledore's office. George went straight for the Pensieve, but it was empty.
George swore loudly. His eyes darted around, looking for anything that could help him. Dumbledore had too many useless doohickeys. Then he saw the firebird on the perch looking at him funny.
"Fawkes. Can you find Dumbledore?" The phoenix nodded. "You need to take us to him or he will die."
"Weasley, you're—" Snape's comment was cut off as George grabbed him and Fawkes' tail and they burst into flames. The flames died and they were next to a semi-conscious Dumbledore lying in rubble.
"You came," Dumbledore breathed.
George felt something tear at his back. He turned to see a horde of charmed skeletons attacking. Snape looked conflicted about helping the man who looked like a first year or the old wizard trembling on the ground, so George made the decision for him.
"Snape, you take care of Dumbledore. I'll take care of the skeletons."
George put up a shield charm around the two professors and summoned fire. It scorched the bones, but they just kept on coming. Apparently charmed skeletons were harder to kill than Inferi, at least in large numbers. Why Voldemort didn't use them all the time was a question to ask when he had time to think philosophically.
George attacked the skeletons with every spell he could think of. Once he had a spare second, he quickly checked on those he was protecting. Snape looked completely clueless.
"Kill the ring with the venom!" he told Snape.
"I can't, Weasley! They are connected—it will destroy him too!"
"He's the greatest wizard alive and I am not going to let him die because you have no idea what to do!"
Fawkes began singing. It dropped something in front of George. The Sorting Hat. Gryffindor's sword appeared from inside of it. "I guess I'm Harry freaking Potter now," George muttered as he chopped the nearest skeleton in half and ran to Snape and Dumbledore. George grabbed the venom and poured it on the sword. Snape was about to protest again when George slammed the blade into the stone on the ring.
"Your turn," George told Snape as he took the sword against the skeletons again. George felt like he was channeling the spirit of Godric Gryffindor as he sliced foe after foe in half. But the skeletons just kept coming and George's young body was quickly tiring.
"Enough, Saintlike One," Dumbledore said. "I am stable enough now. Fawkes, help us get out of here."
George sprinted to his two companions and the phoenix once again burst into flames.
"Saintlike One, you have a lot of explaining to do."
George ignored the Headmaster. "How long does he have?" he asked Snape.
"Probably two and a half years."
George swore again. "I'm such an idiot. I should have said something earlier, but no, I've got to make sure the universe forgets I exist! A year and a half more? That ruins everything!"
"I believe I said there would be two and a half," Snape said.
"If you already had Gryffindor's sword and I wasn't here to realize the danger, Dumbledore would be dead within a year," George retorted. "But it's not enough. It'll never be enough because the one wizard who the world trusts with their lives other than Harry Potter will be dead while the Boy-Who-Lived is still a first year!"
"You knew what I was going to do tonight," Dumbledore said. "You knew there was a Horcrux and yet you risked your life to save mine. Who are you, Saintlike One?"
"I'm George Weasley," George replied.
"Saint George is more like it," Dumbledore said. "But I must ask: do you know where Voldemort's other Horcruxes are?"
George paused. "Why do you trust me now?"
"Many reasons. For one, I can see that you are a true Gryffindor. You wouldn't have been able to summon his sword if you weren't."
"That is true," the Sorting Hat agreed. "I apologize for assuming you belonged in Slytherin."
Snape muttered something under his breath that sounded a lot like "blatant favoritism."
George closed his eyes and sighed. "Very well. Six Horcruxes. Slytherin's locket was hidden in a cave where Tom Riddle tormented the other orphans, but it was taken by Regulus Black, who defected shortly before his death. The locket is now in the possession of the house-elf Kreacher at 12 Grimmauld Place. Hufflepuff's cup was entrusted to Bellatrix Lestrange and it's probably in her vault. Riddle's diary was entrusted to Lucius Malfoy, who knows that it can be used to open the Chamber of Secrets; my best guess for its location is under the Malfoy drawing room floor. Ravenclaw's diadem is somewhere in the Room of Requirement here at Hogwarts, in the 'room of hidden things' version of it. You already found Gaunt's Ring and you now possess all the Deathly Hallows, but you will never be Master of Death."
"I understand that now," Dumbledore said solemnly.
"And the sixth Horcrux?" Snape asked.
"Voldemort himself hasn't realized he made it yet. Back on Halloween of 1981. Harry Potter."
"So, to destroy the Dark Lord, the boy must die?" Snape asked coldly.
"In a matter of speaking, yes," George replied. "Before you start screaming about what that all means, I think there's a way around it. Voldemort wants a body again and if he has a choice, he will use Harry's blood to do so. If Voldemort then attempts to kill Harry again, the blood will tether him to this world while destroying the Horcrux."
"You are insane," Snape declared.
"Trust me. It'll work."
"I think it will," Dumbledore said. "I still wonder, though, how you learned all of this."
"I have been forbidden to speak of it for at least one year after the possessions began. You should be aware, though, that I believe the young Weasley twins have a right to know before you do. Just because I have entrusted you with information does not mean that I fully trust you. You were stupid enough to put on the ring, after all."
"I trust you," Dumbledore said. "That is enough."
"Dumbledore trusts you now?" Fred cried. "Is he insane?"
"Many have questioned his sanity, but he was quite sane after he realized I saved his life," the Saintlike One replied.
"You've probably bewitched Snape and Dumbledore," Fred concluded.
"I thought you knew me better by now," the Saintlike One said. "And I doubt that there's a witch or wizard alive who could mentally battle either of them and win."
"There's a better chance of that than you being a Gryffindor," Fred muttered.
The Saintlike One sighed. "September," he whispered. "Next September and I can tell you everything."
"What?"
"I started possessing your brother September 1st. If we get to that point again, I will tell you everything you want to know about me. Anytime before then and the universe just might end. Literally. For now, take my memory of what's happened tonight," the Saintlike One said as he removed some wisps from his head and placed them in a vial. "Hopefully this will help you trust me between now and Confession Day."
Fred scoffed. Just shut up you tricky git. Before the Saintlike One could stop him, Fred took a quick swig of pumpkin juice. As the liquid went down Fred's throat, George let out a cry and crumpled to the floor.
"George!" Fred cried.
"My back..." George choked out. Fred looked and saw the hole in the back of George's shirt and a bloody gash under it. "I guess he really does have a higher tolerance for pain than me."
"Come on, let's get you to Madam Pomfrey," Fred said as he took his twin's arm around his neck and crushed the vial of the Saintlike One's memories underfoot. He could not bear the thought of knowing what the Saintlike One did to hurt George.
Halfway to the Hospital Wing, Fred felt pumpkin juice enter his mouth. So did the Saintlike One finally remember that George is hurt and want to apologize or is he just mad I shut him up? I guess it doesn't matter, since I'm not letting him come back, Fred thought as he spit the pumpkin juice on the floor.
Bill and Charlie were right. That evil Saint hurts everything sooner or later.
George swore at himself again. He'd forgotten to take care of the injury he'd gotten back at Gaunt Shack. It was nothing to him—he'd had years of Bludger bruises and other mishaps, not the least of which was losing an ear—but Young George would have a much harder time dealing with the pain. George tried to send himself back, but Fred was refusing. He'd be lucky if Fred ever trusted him again.
George grabbed his version of the parchment he enchanted at Christmas and wrote a letter to the young twins.
Dear Fred and George,
I am so sorry. I forgot about when the cursed skeleton hit me—I was a little more focused on saving Dumbledore at the time and in the aftermath, healing myself was never a priority. I understand if you never want me to possess George again, and I'll do my best to respect your wishes.
I beg you, though, to give me another chance. I can tolerate not possessing George but I cannot live with myself knowing that you hate me more than Voldemort. I know from personal experience that you do indeed hate me more than the Chief Death Eater. I've been hurt too and the one who did it I truly did despise more than a Dark Lord I never had the chance to meet. But after I learned that the one who tried to hurt me was trying to protect me all along... I forgave him. I still don't like him, but he has earned my respect. I truly hope that you can offer me forgiveness too one day.
And a request: I told Dumbledore all I know about Voldemort's Horcruxes, but I still think he'll need my help in retrieving some of them. I cannot risk revealing my older self to the Headmaster before Confession Day, so you two are still my liaison with him. I would not dream of asking George to become me again, but would you allow Dumbledore to duplicate your copy of this parchment? You will be free to monitor any further contact I have with him and I can make sure that Voldemort doesn't come back and take over the world. Even one Horcrux not destroyed properly will mean that Voldie-Poo is still kicking and I can't let that happen.
Please at least let me know when you've read this message and what you decide.
All my love,
The Saintlike One