Title: The Half-Blood Prince

Summary: The trio need to a teacher who teaches them new spells for the DA lessons. They asked the room of requirement for one, and it gave them the Half-Blood Prince.

Special thanks to my Beta: Earlyable.

Prologue

Harry, Ron and Hermoine had their heads stuck together during dinner, discussing the current progress of the DA lessons, while being cautious about not being overheard by any of the teachers and especially no Umbridge.

The progress of the members in their little group was amazing thanks to the tutelage of Harry, but recently they had come across a little problem.

It had been getting harder lately to find new materials for the DA lessons. Harry was getting worried about it a bit. These last few lessons he had been repeating a few things, to perfect them more than anything else, but soon he would need new things to teach them.

The problem was that while he was indeed quite good at Defense, he couldn't figure out everything by himself. Even with the aid of Hermoine he had some troubles to find out how exact some spells worked. Most times when they learned a new spell the teacher would show at least once of how they were supposed to do it. Even Snape did it when they had to use spells on their potions.

Ron decided that if they, being Harry and Hermoine, couldn't master the stuff just from books, that there was no way that they could teach the other members.

"What we really need, is someone who can teach us some of the higher level stuff." Ron had said. "No offense mate, but we kind have hit a dry spell with these classes. If you show them how to perfect the wand movement of Expelliarmus one more time I think we'll get a revolt."

Harry blushed. He had told Ron that he had planned to do that one more lesson, because he hadn't got anything else to teach them. He always told Ron what he wanted to teach because Ron actually showed promise in planning how a lesson goes and knew very well who would need more help than other people.

Both Harry and Hermoine had been amazed by the surprising show of talent that Ron had for organization. Especially after seeing the state of his room in the Burrow.

"If only we had Lupin," Harry said glumly, "He taught me most of the spells that I know and that are actually useful."

"Perhaps we only have to find him a way to get him inside Hogwarts." Ron said. "Like the Shrieking Shack or something, or perhaps he can apparate here when it's dark."

"You can't apparate in Hogwarts Ron." Hermoine said a bit exasperated. "You should know that."

"Besides I don't think it's possible for him to come on school grounds without the Toad knowing." Hermoine said. "I mean, if we could get him in, that would solve anything, but if She finds out, who knows what would happen to Remus. Or us for that matter."

"But," Ron began, clearly having an idea, "we can try to ask the room of requirement for him. I mean, so far that room has given us everything we need perhaps we only have to ask."

Ron was actually right, it couldn't hurt to ask. They guessed that if the castle wasn't able to give them the help they needed then no door would appear.

"That could actually work Ron, you are a genius." Hermoine said; making tips of Ron's ears go red. He mumbled something faintly and then he turned back to his food.

They decided to try the next evening. They carefully made their way towards the painting of Barnabas the Barmy, checking if anyone was near with the Marauders' map. This evening they were in luck.

Harry started to walk past it thinking 'we need a teacher who can learn us defensive spells' three times, while the other stood guard just in case of Filch.

When he walked past the wall the last time he looked up and found that the door had actually appeared in front of them.

Ron cautiously opened the door and saw the room they usually had their DA in, and in the middle of that room a person stood with his back toward him.

He turned around and they noticed that he was a black-haired youth, perhaps a few years older than they were.

"Good day, I am the Half-Blood Prince, and I believe you asked for me."

TBC