A/N- Hey there! If you missed it, Children of the Sun and Moon also updated!
This story here is based off of a great bit of artwork for Sherlock going around where Sherlock and John are members of the DADA club and Sherlock is having trouble conjuring his Partronus. John suggests he needs a different happy memory, and Sherlock thinks about them meeting on the train to Hogwarts. I thought I would expand that idea a bit, so here comes this fairly short chapter-the first of a few fairly short chapters of a fairly short story. But hey, I liked the idea ^_^.

As John limped down the aisle of the Hogwarts Express he passed compartment after compartment filled with loud, excited students. He smiled to the ones he knew, and nodded to the odd polite wave from random first years. He could almost see them quivering, and a few that had to be muggle born looked positively green around the gills. Ahead of him a compartment opened and John saw his year mate Mike Stanford back out.

"Oye!" John waved, pulling his trunk along behind him and trying to limp a bit faster, "Mike!"

Mike was a Hufflepuff to John's Gryffindor, both of them Fourth Years. They'd taken Medical Charms together last year, and had bonded over a mutual love of muggle sports-slow that they were.

"John! So, Gryffindor still hasn't kicked you out yet?" Mike reached forward to grasp forearms with John, while casting an odd little glance back to the compartment.

"No, I don't think they're planning on it either. Though, I suppose I can always count on Hufflepuff taking me in!"

"We're good Finders, John, not good Martyrs. Why aren't you settled in somewhere with your nose stuffed into Madam Pomfrey's text book?"

"I can't find an empty compartment. It's like everyone's been chewing talky-taffy. John shrugged and peered around Mike when his friend's gaze shifted back to the door, "There anyone in there?"

"Um, just a new first year-Sherlock Holmes. Perhaps you know his older brother Mycroft? He's a Ravenclaw Prefect,"

"Can't say I do," John followed Mike to the door and peered inside the compartment, where he saw the tallest first year he'd ever come across. The boy had masses of dark curly hair that looked like he frequently yanked at it. Cradled in his long fingered hands was a scull of some sort which he absentmindedly petted.

"Cor, he's tall," John blinked when the younger boy looked up with the most startling pair of glaz eyes he'd ever seen and leveled him with a cool stare.

"Wanna meet him?" Mike asked it like he knew some sweet joke, but John has already shouldered his way into the compartment.

"Hi, I'm John Watson," John's grin faded and his outstretched hand fell as Sherlock just stared at him. The boy turned to Mike, "Mike, may I use your wand a moment?"

John almost flinched. Someone's wand was a highly personal thing, but here was Mike, one of the most cautious Hufflepuffs he knew, patting his pockets for his wand. Grimacing, he said,

"Sorry Sherlock, I left it locked in my compartment,"

Sherlock sighed and tapped mournfully at the skull.

John glanced at Mike, surprised to meet his friend's eyes, and even more surprised when Mike nodded at Sherlock, urging John on, "Er… Here, use mine," John pulled his wand from his pocket, first brandishing it, then expertly flipping it to offer it to Sherlock by the well-worn grip.

Sherlock's eyes travelled slowly up the length of wood, then even more slowly up John's arm and to his face, studying John again like he was revising an opinions.

"Thank you," Sherlock wrapped his long fingers around the wand and hefted it, twirling it a moment before tapping the skull and whispering an incantation too low for either Mike or John to hear. John accepted his wand back as the three stared expectantly at the skull.

"Ash, surprisingly rigid for Dragon Heart's string, don't you think?" Sherlock's quiet voice made John jump.

"How… how did you know that?"

The skull in Sherlock's hands twisted around to fix hollow eye sockets on John, and in Sherlock's voice replied, "The same way he knows you fought for Dumbledor's Army, and that you have a psychosomatic limp from The Battle, and that you play Keeper on the Gryffindor team, and that your brother's an alcoholic,"

John and Mike stared in stunned silence as the skull rocked in Sherlock's loose grip and turned back to face the now triumphantly smirking first year.

"Finally got that spell to work?" Mike managed, just as John surged forward excitedly.

"This is-," John reached forward and Sherlock flinched, but John missed it as he gently took the skull from him, "Fantastic!"

Sherlock's head snapped up and the skull's jaw fell open with a clatter, "That's not what people normally say," commented the skull, sounding shocked.

John smiled at Sherlock, then asked the skull, "And what do they normally say?"

But the skull burrowed its face in his palm and declined to answer.

"…piss off," Sherlock murmured as he accepted his skull back from John. The unsure expression on the boy's face morphed into a small but genuine shy smile as John laughed.

"Well I think that is fantastic. How'd you do it? I was never good at charms like that,"

Neither boy noticed when Mike slipped away, leaving John to badger Sherlock with questions. The younger boy traded answering with his skull. The rest of the train ride found them locked in conversation as Sherlock explained to John how the feel of his wand told him the core was Dragon Heartstring, and the bit of odd discoloration on the ash showed that the most used spell was a hangover cure. Sherlock told him that the way he moved and appraised his surroundings, as well as his age, had tipped him off that he'd been a part of the Battle, and that the callouses on his hands from his broomstick betrayed his position as Keeper.

John's anatomy text lay forgotten atop his trunk as he listened to Sherlock talk. When the train pulled up to the Hogwarts platform, John leaned over to Sherlock,

"You did get one thing wrong about me, though," John laughed as Sherlock hounded him all the way from the compartment to the Thestral-drawn carriages.

At Sherlock's sudden silence, John turned with a sad smile, "I'm sorry, I didn't think… Maybe you wouldn't have been able to see them,"

Sherlock frowned at John's sentiment, "No matter. Now, tell me!"

John just laughed and climbed into his carriage with Mike and Gryffindor second year named Molly Hooper. Turning as they clattered away down the bridge, John laughed again to see Hagrid trying to drag a fuming Sherlock toward the first year's boats.