"John! Come on! Get up!" Sherlock whispered loudly into his best friend's ear. "You promised to help me with my Patronus!"
John sat up with a groan, running a hand through his rumpled sandy-blonde hair. The Gryffindor boys' dormitory was near silent except for the occasional snore.
It has to be around 2 am, John thought. What a disgusting time to be awake. But Sherlock looked so eager and expectant that John reluctantly pulled himself out of bed with no more than a "One of these days, I'm going to kill you, Holmes," by way of insult.
Once John had pulled on some clothes, Sherlock led the way down to the Gryffindor common room. As they were about to creep out, a thought occurred to John.
"What if somebody sees us?" he hissed. "We don't exactly have Invisibility Cloaks."
"No, but luckily, I'm rather talented at Undetectability Charms," Sherlock replied rather smugly. "I charmed our scarves earlier. Anyone who sees us won't notice us. Their eyes will slide right over us like we aren't even there." Sherlock handed John a scarf.
John put on his scarf, glanced down to see if he could still see himself, and found himself looking at a spot in the carpet three feet away. He opened his mouth to talk to Sherlock but the other boy had disappeared.
"Sherlock?" he whispered, reaching out with one hand. Sherlock's slim-fingered hand took hold of his.
"Right here," he said. "Sorry - we'll have to hold hands so we don't lose each other."
Together, they climbed out of the common room and started down the hallway.
"Where are we going, again?" John asked. He decided it was rather disconcerting, talking to someone you couldn't see.
"The Room of Requirement," Sherlock whispered back. He lead them through a few odd tunnels and down some secret staircases until they were standing in front of a wall. Sherlock let go of John's hand.
"I have to open it up. Give me a moment," he said before John had time to panic.
John listened to his friend pace back and forth a few times. Suddenly, a door appeared in the wall. Sherlock found John's hand again and lead him to the door.
"You can take your scarf off now," he said once they were in.
With a sigh of relief, John took off the enchanted scarf and flung it across the room.
"That charm won't stick around forever, will it?" he asked, appreciating being able to look down and see his own feet again.
"It'll wear off by the morning," Sherlock answered as he readied his wand to practice.
The Room had taken the shape of a classroom filled with squashy armchairs and pillows. John sat down on one of the chairs, exhausted.
"Can you make a Patronus first, so I can see how it's done?" Sherlock implored.
Yawning, John stood up and pulled out his wand.
"Expecto Patronum!" he said, concentrating hard on his happiest memory - the day he and Sherlock had lead the Gryffindor Quidditch team to victory against Slytherin. His Patronus, a hedgehog, burst from the end of his wand in a swirl of silvery light and began trundling around the room.
"Just concentrate on a happy memory, Sherlock," John said.
"All right." Sherlock closed his eyes, concentrating.
"Expecto Patronum!" he said, but all he got was a half-hearted puff of silver mist.
"Choose a happier memory," John urged. "Come on - you have to have at least one!"
"What memory did you use?" asked Sherlock, looking a bit displeased that he couldn't do something John could.
"Oh, um... the time you and I helped win a match against Slytherin and they lifted us up on their shoulders and cheered," John said, a bit red in the face. "Now go on - try again."
Taking a deep breath, Sherlock tried again.
"Expecto Patronum!" he yelled. A sudden wave of light blinded the two boys as Sherlock's Patronus bust out. It was an otter.
"Blimey, that was strong!" John said, rubbing his eyes. "What memory did you use?"
Sherlock turned red and muttered something indistinct at the carpet.
"What?" John asked.
"I... um... I..." Sherlock mumbled, then rushed out, "Iusedthedaywemet."
"You what?" John was dumbfounded.
"The day we met. That's what I thought of." Sherlock suddenly became very interested in a nearby pillow.
John pulled his friend into a hug. After a few moments of stiff awkwardness, Sherlock hugged him back.
"You're all right, Sherlock Holmes," John said, pulling away and teasingly punching his arm. "You're all right."