This is the story I wrote for slythindor100's 25 Days of Harry and Draco in 2014. It has 25 chapters and the rating will eventually go up. Thanks to the mod at the comm for the wonderful photo prompts which helped shape the story. The titles of the chapters refer to the prompts used for each one.
There are plenty of plot twists ahead, as well as slash of the Draco/Harry variety.
Winter 2018
Harry trudged alone in the snow, occasionally raising his hand to touch the Weasley scarf wrapped tightly around his neck, a comforting reminder of a time irrevocably lost.
He glanced up at the facades of the stores in High Street, the Hogsmeade buildings dappled with the waning light of the evening sky. Bands of cobalt blue and Slytherin green hung suspended high above him; they reminded him of the Northern Lights Hermione once showed him in a travel book.
Harry stopped in front of the Post Office, the muted hooting sounds coming from within lightening his mood ever so slightly. They brought to his mind Hedwig and the carefree time of childhood, when magic was new and the only nemesis he faced was…
His face twisting in a painful grimace, Harry squared his shoulders and opened the door. If the rumors Ron had heard were right, he might have an opportunity to correct things. It was a very slim chance, but Harry always had the tendency to doggedly hang on to hope.
The tinkling sounds from the doorbell alerted the clerk, who closed a ledger and then looked at him.
"What can I do for the Minister of Magic?" the wizard said with an unctuous smile. "Allow me to introduce myself, Mr. Potter. My name is Chronus Skemp."
Harry nudged up his glasses with his thumb. For a moment the man seemed to be surrounded by a halo, his silhouette shimmering in and out of focus as if he was inside a Ministry lift which receded into the horizon.
"Is it true what they say, about your owls?" Harry said wearily, his fingers fishing inside the pocket of his cloak to brush against soft vellum.
"I assure you it is true, Mr. Potter." Skemp's weathered face broke up in a slight smile. "The Muggles grow ever bolder, and they probe the wards around Hogwarts with sophisticated equipment as they try to find us."
"So if I send a letter…" Harry trailed off, his gaze sliding along the perches where the owls stared down at him, some with benign expressions, and others unfathomably.
"The owls fly into the night," Skemp mused. "They are charmed to pass through the wards that Ms. Granger-Weasley designed herself, though they have been subtly altered by the Muggle probing which causes the weird colors of the sky. The strange mix of both our worlds - quantum and magic - has unusual consequences. Some recipients get their letters in the past."
"How far into the past?" Harry gripped tightly his Hawthorne wand, the only memento he kept from Draco and that winter long ago when hope was briefly renewed and life appeared to be an open road.
"It depends on the owl you choose." Skemp lifted his arms and made a sweeping gesture around the room to indicate the owls, many of which ruffled their feathers as if they were bothered by the scrutiny. "I've been made aware of letters received as long ago as twenty years."
Harry nodded as he walked along the walls, hands stuck in his pockets as he stared intently at the owls.
"Choose wisely," Skemp said dryly and then opened the ledger, his fingers picking up a white quill.
Harry's boots thudded softly in the wooden floor, the hooting of the owls calming his nerves when he made his way around the room as he tried to gauge the suitability of the birds for this task. How would he make his choice amongst the many owls, tawny, Eagle, and snowy?
His gaze slid towards a snowy owl which hooted soothingly at him. He was tempted to pick it based on the strong resemblance to Hedwig, but then he was met with the angry stare of the huge Eagle owl next to it that had flapped its wings at Harry and contemptuously turned its back.
His heart beating madly against his ribs, Harry made his choice based on his instincts. He stood on tiptoe and the owl grudgingly consented to step into his outstretched arm, talons gripping tightly the sleeve of his cloak.
Harry fished out a parchment from his robes and made quick work of attaching the letter around the claw of the Eagle owl, ducking his head now and then to avoid the owl's beak as it attempted to peck him.
Before he let go of the owl carrying his precious missive, Harry leaned down and whispered into the bird's ear, "Draco Malfoy, Hogwarts in our Eight Year, winter 1998."