Summary: Sirius' daughter comes to school and befriends Harry and friends. That's when she starts noticing Remus Lupin as more as her father's best friend. Meanwhile, Voldemort and his Death Eaters are taking over. This takes place in Harry's sixth year, but Sirius is still alive.

Warnings: This story will contain a teacher/ student relationship. Don't like, don't read.

Disclaimer: I own nothing except for Mystilla. Everything else is JK's.

A/N: I had posted this earlier, but took it down to add all of the above information and stuff. Enjoy!

Chapter One- Meeting Mystilla

As the Hogwarts Express got closer to the school, Harry Potter and his friends, Ron Weasley and Hermione Granger,

turned their conversation towards the upcoming school year. This would be their sixth year attending Hogwarts School of Witchcraft and Wizardry.

"The Defense Against the Dark Arts teacher can't possibly be any more horrid than Umbridge," Harry shuddered at the thought of their last year professor. They were deep in discussion about who would take her place when a commotion in the hall distracted them.

"Get outta here!" Draco Malfoy roughly shoved a girl out of the compartment he shared with his thugs, Crabbe and Goyle. She seemed to be their age, Harry reasoned. She had shoulder length dark brown hair and warm gray eyes that lit up when she saw them. She marched purposely towards them.

"Hey, you three don't mind if I sit with ya, do you? I mean, we're almost to school, so I shouldn't bother you all that much. Got kicked out of the last compartment, and I really don't feel like standing the rest of the way."

"Sit on down!" Hermione gestured at the empty seat next to her. The girl smiled gratefully and walked over to her and sat down. Harry, Ron, and Hermione all introduced themselves, then looked at her expectantly. Her eyes seemed to linger on Harry before she answered.

"I'm Mystilla, but you can just call me Misty."

"So, why did you get chucked out by the Slytherins?" Ron asked. Misty grinned.

"I've really gotta think before I speak," when they continued to look confused, she explained. "I went on a rant about how much I hated Slytherins before realizing that the only people in the compartment with me were Slytherins!"

"You're a new student here, aren't you?" Hermione asked. At Misty's nod, she asked, "Then how do you know you hate Slytherins?"

"My father told me that they were practically all evil," she explained.

"If your father went to Hogwarts, then why haven't you been coming to Hogwarts before this?" Hermione frowned.

"I was being given lessons by a tutor at the orphanage in which I was raised, before I recieved a letter from your Headmaster telling me that he knew who my father was! Knows him quite well, actually," she added mischieviously.

"If Dumbledore knows him, then we probably do, too," Harry said thoughtfully. Misty gave him an odd look.

"Oh, I think maybe you do."

"Then who is he?" When Misty did not reply, Harry asked instead. "What's your surname, then?" The train jerked to a stop and people gathered in the hall, waiting to get off.

"You'll see at the Sorting, won't you?" Misty winked at them and disappeared into the mad crowd in the corridor.

"She reminds me of... But he would said something, wouldn't he? ...Unless... But that doesn't explain how..." Hermione muttered as they exited their compartment. Ron rolled his eyes at her and led the way through the throng to get to a carriage.

The first thing any of them realized when they entered the Great Hall was that Remus Lupin once again sat at the Head table. They beamed and waved at him. Smiling, he waved back, recieving a glare from Snape as he did so.

"I can't believe he came back!" Hermione exclaimed. "After, you know..." She was referring to his being a werewolf, and that he had resigned in their third year after nearly attacking the three of them and Snape.

"He must have realized that the only one who cared about that was him. And Snape and the other Slytherins, of course," Harry added, nodding towards the Slytherin table. All of the students seated there were whispering to each other with constant dirty looks at Remus. Harry ignored them. "At least this year we won't need the DA." He fell silent as McGonagall swept in, this year's first years in tow. Misty, they noticed, was talking quite animatedly to the professor, who looked a little startled.

"Before I call the names of the new first years," McGonagall called. "We have a new student who will be entering Hogwarts as a sixth year. This," she gestured to Misty, who stood next to her, grinning. "Is Mystilla Black."

Ron and Harry's jaws dropped, but Hermione whispered excitedly, "I knew it!"

The Sorting Hat had barely touched her head when it cried, "GRYFFINDOR!" Misty stood up and bounded over to them.

"Oi, budge up," she shoved Harry aside a little to sit down next to him.

"Black?" he asked, eyes wide. Misty nodded and turned to watch the Sorting now taking place.

"You mean, you're Sirius' daughter?" Ron asked quietly. Misty smiled and nodded before turning to Harry.

"So, I guess that means you're like my Godbrother, doesn't it?" Harry stared at her as she turned back to the Sorting. Remus was also staring in their direction. He caught Harry's gaze and mouthed, "Did you know?" Harry shook his head. Remus sighed and turned back to the first years.

"If it's any consolation," Misty said as she piled food onto her plate. "I'll explain some things tonight." Harry glanced at the staff table before replying.

"Can Remus come, too?" Misty looked puzzled for a minute, then grinned.

"Oh, yeah, Dad's best friend! Of course! I've been wanting to meet him, actually, after everything my father said about him," she looked carefully at Harry before adding, "He also told me quite a bit about you, Oh Great Boy Who Lived. Says you have a knack for trouble. Speaking of which," she put her arm around him in said in mock seriousness. "Harry, old chap, I plan on borrowing that map of yours sometimes."

"Anything you do late at night, bring us along!" Ron exclaimed as he took another chicken leg. Misty laughed.

"Dad tells me the three of you are quite adventurous! I'll be sure to let you know when I plan to wander around at night."

Up at the staff table, McGonagall muttered to Dumbledore, "We now have both a Potter and a Black at this school again. I shudder to think what they will do!"

"And a Lupin," Dumbledore raised his voice. "Remus, could you pass me that custard tart, my boy? Thank-you!"

"This is going to be an unusual year," McGonagall sighed.

More to come soon...