This initially was a plot bunny when I started thinking about the endless pocket charm as a way for Harry to keep necessities on his person, even after a strip search. There's so many times he has a trunk as jewelry (earrings in Akren series, Lily's locket as a trunk or a Gringott's trunk in an amulet, etc.). They always mean he has to unshrink the whole thing, rather than just reaching for a given thing. This pocket would have to be internal, but no 'Jack Harness naked-gun-draw'. I'm going more for cartoon hammers. Then I went to see the new X-men movie, and Gambit was HOT! I hate Rogue as a character, and in the movie-verse, he'd be something like 15 years older, so presto!
Word to the wise, I couldn't get the real 3MI incident (3/28/79) to fit into the timeline of the movies, as it would make Scott almost ten years older than they portray him. Also, as I can't seem to find a decent timeline for the X1-X3, assume:
end WO:summer 1986 (Scott's age change 18-32ish, season from foliage when see Prof X and what people wear in the FQ crowd scenes)
X1: summer 2000
X2: fall 2001 assuming a bit over a yr later, given the level of training Rogue seems to have, her relationship with Bobby, and a yr is a reasonable time to assume Logan took to explore his past
X3: spring 2002 supposed to be 4-6mo after Jean supposedly died
This prologue is meant to take place March 97- 6th year
This night before the Equinox, Harry was once again abandoned by his friends as they actually needed to sleep. Harry had slept his necessary 5 hours, and it was now 4 in the morning, at least 2 hours before anyone else got up. He had found a charm that worked like a copy machine back in 3rd year, letting him copy up to 15 pages from a book at a time. He had combined the fruits of these sleepless nights, and boring winter holidays, spent in the library, into a small journal he'd had Fred buy for him in Scrivenshaft's. It had endless pages, and allowed for search charms, so he could always find a given spell type. No one knew that he now probably had compiled the most complete grimoire on enchantments.
His project for the last couple years, and the reason he'd started his compilation, was to find a way to make sure that he would always have necessities at hand, even if he was separated from his trunk, or strip-searched, especially during the summer. Last week, he had gotten a brain-storm; he'd been nervously rubbing a scar on the back of his neck, from where Vernon had pushed him against the hot oven rack that summer when he hadn't been quick enough with bringing in the chicken breasts, 'Dudley was starving on his diet, don't further delay his nourishment'. He remembered from biology in primary school, that the first layers of skin, and more than that in scars, were dead. Therefore, if he could flay a shallow hole between layers of dead skin, and keep it open and intact, he could cast an endless pocket charm on the hole like it was a leather purse. He'd asked Professor Flitwick about the plausibility, as a hypothetical yesterday, and he'd agreed that it was possible, but would take a lot of power and precision. Given part of the more advanced version of that charm added an organizational charm that put the thing you needed most at your fingertips...
Finally, he had compiled the list of charms he'd need: shielding and stasis, to keep the slit intact and safe from friction or sunburn-induced peeling, the actual expansion charm, and a charm meant to complement the pocket charm, a charm to make the contents weightless while in the pocket. For his first attempt, on a cheap pencil envelope to serve as his secondary storage, he'd initially forgotten the weight charm, threatening to dislocate his shoulder when he tried to pick it up with four years worth of school texts in it.
By 7:30, he had a veritable 'Mary Poppins bag' embedded in his skin and another tucked in his pocket. Testing it a few times with old homework scrolls he found in his rucksack, he decided he'd keep his compiled book, some money, the Marauder's Map, Siri's dagger (in a sheath), and his photo album in it. There would be lots of extra room, but he'd think of other useful contents later, he had to meet Ron and Hermione in the common room so they could go down to breakfast.
When they returned from the cave, Harry knew that the Headmaster was dying. He could feel Dumbledore's magic sputtering out. Therefore, though he did struggle against the restraints, he saw Snape commit a mercy killing, not murder. He may not like the snarky git, but he saw the tears lingering. He could also respect Draco's fear. He chased them out, pushing a message to Snape, /Get going, but stay in touch if you can. We still need the information. I'm sorry about the pensieve./
The next week, he spent either meditating or copying books into another endless journal. He'd started by copying the spell lists from his old school books, and found copies of the next books in the Transfiguration and Charms sets in the Library. He broke into Snape's quarters, copying his Potions and Offensive Magic, leaving an apology and explanation as a bookmark when he returned the Half-Blood Prince's book. When Hermione fell asleep on her books, he took the opportunity to copy her Arithmancy and Runes books. By the time the end of final exams came around, Harry had a significant fraction of the library copied to his two journals.
Though his Occulomancy shields were pretty puny under direct assault, he'd constructed clouds of Cruciatus memories to surround a multi-lock trunk in his mind. His knowledge was filed by subject and year, with chronological continuous filing of memories under the guard of a Green Tree Boa like the one he'd freed, and a juvenile Basilisk. Each lock was triggered by his feelings for a given person. Hermione guarded his knowledge of minutie, and he hoped to add to that compartment with Arithmancy and Runes. His attitude about Aunt Petunia was the key for house-keeping and cooking knowledge, both mundane and magical. His mum guarded Charms, his dad, Transfiguration. Ron was strategy and flying, his respect and sorrow for Snape gave entrance to Potions.
Ginny was not happy that he broke up with her, but she accepted it eventually, mostly after a little talk with Hermione, and he promised to reconsider after the war.
When he packed up to go to Privet Drive, he added the new compilation book to his neck 'pocket'. Most of his now-redundant school stuff was in the pouch in his front trouser pocket, his wand in the back pocket. He decided he'd spend some of the time he was locked in altering the side seam of his favorite pair of jeans to act as a hip holster.
While he was waiting for the Dursleys to show up, he tested the pocket to make sure it wouldn't set off any alarms. Professor Flitwick had said that it shouldn't, as the professionally-made items did not, but he needed to be sure. Right now, he was close enough to the portal, and it was soon enough after term, that he could probably talk himself out of trouble. He threaded his fingers under his hair, his hand disappearing up to the second knuckle. Waiting a few minutes, he did a mental happy-dance. It had worked, and was basically undetectable!
When Dudley came knocking to annoy him the next week, Harry was in the process of re-distributing his belongings before he left for the Burrow. He caught him in the process of drawing the dagger for sharpening.
Dudley's jaw dropped, rasping out, "What the he-ck!"
"Dudley, don't say anything. I'm not going to stab you."
"But, it's like a cartoon! Like Tweety pulling a hammer out of nowhere."
"Actually, its more like a Mary Poppins bag. Remember the Dementors? They were one of the first waves in a civil war. I can't have visible battlegear..."
Dudley's face returned to normal, but a bit thoughtful, "Yeah, I could see lugging food, clothes and a tent would be clumsy. You see photos of soldiers, their packs were almost as big as they are. And you're pretty shrimpy still. Are you ever gonna grow?"
"You see the point. As for my size, there are people in my world that speculate, with some evidence, that the more powerful someone is, the slower their body is to reach growth spurts. Someone told me that my Headmaster didn't have his secondary-school growth spurt until 2 weeks before he graduated, he was almost 18, and I'll be 17 in a month...Shouldn't you be out jogging, Aunt Petunia said something about an exercise regimen from your coach."
Dudley smacked himself in the forehead and bolted.
The time until his birthday went fairly quickly, until it was time for the March of the Seven Potters. It was really quite disturbing seeing Bill eye the Fleur-Harry like that, but also made his stomach flip. The wedding went well, and Harry didn't tell them about his body pocket, Ron and Hermione were under the impression he didn't bring much with him when they escaped. He missed Hedwig desperately, but he couldn't have brought her with him on their hunt anyway.
Whenever he had watch, he'd read from his books. He had Hermione quiz him while they walked. He found that his work to set up filing in his head made him able to learn better. Before, he had too many useless facts, or at least facts unrelated to his current actions, floating around; thinking about the best way to make a souffle while writing a Transfiguration essay was counterproductive. Hermione appreciated the time spent reviewing, so she never complained he was making her think and talk too much while she should be navigating.
They were in Godric's Hollow, heading to visit Madame Bagshot, when Harry's scar twinged.
"Ron, Mione, go! Something's fishy here. I'll meet you at the end of the lane."
No sooner than they were out of sight, did he start hearing hissing. Realizing it was probably Nagini, he started off in the other direction, but he found the way blocked by Bellatrix. As subtly as possible, he palmed his packet of clothes, books, and his cloak under his hair, into the hidden pocket, drawing his wand with the other hand.
"Ah, hello, Bella. Fancy meeting you here. Come to bring me to Tom?"
"Don't call my Lord that filthy name! Petrificus Totalus."
When they arrived, she had her husband throw him into a cell so she could go report in.
Harry, concentrating fiercely, managed to force his Patronus to the shape of a wren to send a message for Ron and Mione, that he was taken, but fine, to not come after him He wasn't sure how long it would keep its shape, but he hoped for the best. He then transfigured a chunk of dirt into a wand-likeness, then put his real wand away. Scooting into a corner, he waited.
It didn't take long, as Tom, Bella, and Wormtail came in.
"Hello, Harry. I see you had a bit of a bad day."
"Hello, Tom. I see your father's house serves you well. I wasn't aware Muggles needed dungeons. Or are these a new addition?"
"Foolish boy! Show some respect to your betters."
"Yet by pureblood definitions, I am your superior, your Muggle blood is closer than mine. Father versus maternal grandparents. Or do your lackeys not know?"
In response, both Voldemort and Bella cast Crucio on him. When he lay gasping on the floor, Wormtail broke the fake wand.
Over the next days, he was whipped, cut, drawn on with acid, and cursed in various ways. Voldemort had even Marked Harry on the back, a huge skull spanning from his shoulder blades to his waist, the snake's tongue extending onto his upper thigh. Finally, McNair decided to be clever and suggest giving Harry deaging potion in a dose to subtract more than his age. All the while, Harry had been taking advantage of the fact that most of Voldemort's blood magic was based on the blood sample from the graveyard, and chipping a hole in the anti-apparition wards. The morning that McNair entered with a vial was also the day Harry had a weak point almost big enough. He Apparated as McNair started pouring, splashing part of the potion into Harry's mouth.
I'm aware that Godric's Hollow was Xmas eve, but let's just assume some things clicked earlier, alright?