John looked back at the castle for the last time. He couldn't quite believe he was leaving Hogwarts for good this time. It housed so many memories, and he was sad to leave. John knew he needed to move on to the next step in life but it was still a bit daunting to leave the comforting familiarity of Hogwarts behind.

The whistle for the train sounded, and John quickly hopped on board with his trunk. It was happening, whether he liked it or not. He had been measuring his life in lasts this week. Last time he would take exams. Last time he would pull an all-nighter for a grade. Last time he slept in the dorm. Last time he would eat breakfast in the Great Hall. And now, here he was, on his last train ride away from Hogwarts.

John made his way down the train, looking in on the different compartments and seeing lots of students, but not the one he was looking for. Finally, he noticed the familiar curly black hair in a compartment in the back. He slid open the door and stepped inside. Sherlock didn't look away from the window until John had put his trunk away and sat down. His eyes did their familiar focusing in on him before he smiled.

"It will still be here, John," he reassured, going back to looking out the window.

"I know that," John said defensively. "It's just—"

"It will be here without you," Sherlock finished. John glared at Sherlock before looking away. They rode in silence for a while before Sherlock stretched his feet out into John's lap. John pushed them away and Sherlock just set them next to John.

"You're impossible."

"No, just improbable," Sherlock shot back, and they smiled at each other. They talked about John's plans to be a healer once he got his NEWT scores in, about the experiments Sherlock wanted to run this summer, about seeing each other again and writing and keeping in touch. Somehow Sherlock made John more relaxed, and he found himself often listening to the cadence of Sherlock's voice and watching Sherlock's eyes dart about the compartment. This, too, would be something to miss.

As usual, they got lost in each other. They talked and they didn't. They smiled and they didn't. They touched, and remained touching. John kept thinking about Sherlock's lips, his curls, his voice. Kissing Sherlock would be—well, John imagined it would be really heavenly. He'd kissed plenty of others, earning him the nickname of Four Houses Watson, but Sherlock…well, Sherlock didn't have much interest in people. He might not have been kissed at all, ever. The thought made John ache with longing to press his lips to Sherlock's.

All too soon, it came to an end. Sherlock had nudged John that they were getting close, so John had pulled both of their trunks down as they waited for the train to stop. It came in right on schedule, and Sherlock got up to leave, and this really couldn't wait any longer.

"Sherlock, wait," John said, standing up. They were already close in the small compartment; it wouldn't take much to just close the final inches between them. Sherlock turned back towards John, and John lost whatever else he was going to say. He tried to think of it before deciding to just get on with kissing. He grabbed Sherlock's shoulders and leaned in, giving Sherlock plenty of time to pull away, but instead, Sherlock leaned in, too.

And then, they were kissing. They were actually kissing. Sherlock's lips were soft, pressing gently against his. Sherlock's hands came to circle John's waist and John, emboldened by Sherlock's willingness, ran his tongue over the seam of Sherlock's lips. They parted, and John's tongue slipped inside to meet Sherlock's. John slid his hand up into Sherlock's hair and Sherlock groaned into John's mouth. They kissed for several minutes, until they both seemed to come back to themselves and realized where they were. They pulled apart, and John shuffled his feet, suddenly embarrassed. "Er—" he started.

"Finally," Sherlock said, rolling his eyes. "It took you long enough, John, honestly."

"Oi, you prat, I didn't see you trying to kiss me, either," John replied, smiling. Sherlock merely glanced away, rolling his eyes. He reached out to take his trunk but John intercepted, taking his hand instead. "Wish I'd done it sooner, though."

Sherlock was staring at their joined hands. "Visit me this summer," he said suddenly. "I'm going to go mad. Mycroft will try to micromanage me into an inch of my life. On second thought, let me visit you."

John laughed, squeezing Sherlock's hand. "We'll work something out," he promised.