Summary: On Buffy Summers 16th birthday she is called as a Slayer. Before Merrick can find her she is found by, Charles Xavier. He and Buffy's cousin Scott bring her to Xavier's School for Gifted Youngsters where they begin training her to control her powers, both mutant and Slayer.

A/U: Pre-Season 1 of BTVS.

Pairing: Buffy/Rogue

Disclaimer: Joss Whedon and Mutant Enemy owns Buffy the Vampire Slayer. 20th Century Fox owns the rights to the X-Men movies. Marvel Comics owns the rights to the X-Men comics.

Author's Note: The first thirty or so chapters take place in the original X-Men trilogy, even the hated X3. Then I will take the story into BTVS to see what changes Buffy would make there. And then finally I will conclude the story with Day's of Future's Past. I like the movie but I'm not sure how to get Buffy that far into the past. So I may do the comic version that the movie was based on instead. If anyone has an idea of how to add Buffy into the movie version of DoFP I'm all ears.

Prologue

Los Angeles, California—July 1989

Scott Summers stood with his cousin, Buffy, as she entertained his friends. He had been asked by his aunt and uncle to watch her that evening so they could go out. So he had brought her along to his friend's party.

It was getting late and he had promised his aunt and uncle to have Buffy home by eight o'clock that evening. They were walking down the hall of the Elks lodge, where the party was being held, towards the front door as suddenly, a jabbing pain shot through the back of Scott's head and into his eyes. "Ahhhh," Scott screamed, bending over, covering his eyes as they started to water.

"You all right, Scotty?" Buffy asked concerned. The pain of losing her cousin Celia, Scott's sister, just two months earlier was still fresh in her mind. She didn't want to lose Scott too, so that made her worry when he had screamed out in pain.

Scott managed to nod. The pain was intense. So intense that his eyes felt as if they were trying to explode out of his head. He bumped against a wall. The agony seemed to echo around inside his head.

"Are you sure, Scotty?" Buffy asked again.

Scott didn't look towards his cousin. "My eyes ... my eyes are killing me," he told her.

"Let me see, Scotty," said Buffy as she tried to look at Scott's eyes.

"My ... eyes ..." Scott groaned in pain. Buffy could see that his eyes were watering so badly that tears were literally streaming through his fingers. "... they're burning ..."

Suddenly Scott could feel the pain come together at a point above the bridge of his nose. And then it vanished, as if it hadn't been there at all. Instead there was energy, flowing in his head. Energy he could feel like water running through his fingers.

"Scott should I get someone?" asked Buffy as her worry for Scott worsened as he looked up, taking, taking his hands away, and revealing to her for an instant that his eyes were merely bright red embers in his head. Featureless but for the color. "I'm getting help Scotty, stay here. I'm getting help, hold on." She turned to run, when suddenly behind her there was a massive blast of energy that smashed into the wall causing the wall to explode.

Buffy turned back to look at the massive hole. "I'm getting help Scotty," she said and turned and ran heading back to the party looking for help for her cousin.

May 1996

"I want to spend time in New York City," Marie said, smiling at David who was sitting on the edge of her bed.

"You going to live there?" David asked.

"No," Marie said. "Niagara Falls, then into Canada. Toronto, west to Calgary, then on to Anchorage."

"Wow," David said, clearly impressed. "Won't it be kinda cold?"

"Of course it will," Marie said, laughing. "Otherwise it wouldn't be an adventure."

"When are you gonna do this?" David asked.

Marie shrugged. "I don't know. After school, but before college," she said as he reached over and rested his hand on her shoulder. "So, what do you want to do now?"

"I don't know," he said as he moved closer. "What do you want to do?"

"I don't know," she managed.

He turned her slightly so they were facing each other, then slowly he moved forward until he was kissing her.

It was as if a surge of electricity shot through every nerve cell in her body.

David's eyes snapped open. His hands locked around her in a terrifying grip.

She tried to pull away, but it felt as if he were pouring his every thought, his every wish, his every dream into her head.

Energy crackled around them, until finally she managed to pull away.

He dropped to the floor, his eyes open wide.

The next thing she knew she was screaming.

January 1997

At the home of Joyce, Hank, and their daughter Buffy Summers … Buffy woke up with a start and looked around her room disoriented from the dream she had just had. "What a weird dream," she said.

Across the country at Xavier's School for Gifted Youngsters, Charles Xavier exited Cerebro heading for the elevator. He had just located a mutant just now coming into her powers. He was slightly concerned as how he would tell Scott that is now 15 year old cousin was a mutant.

~Scott I need to see you in my office.~ Xavier telepathically projected towards the man he considered like a son.

Ten minutes later Xavier was in his office waiting for Scott as the man entered the office and sat down across from Xavier. "You wanted to see me Professor?" Scott asked, of course he knew that Professor Xavier had wanted to see him. But it was still polite to ask the telepath anyways.

"What I have to tell you is…" Xavier started. "Difficult."

"What is it Professor?" asked Scott with a look of concern.

Xavier let out a sigh. "How much contact do you have with your cousin, Buffy?" he asked.

Scott smiled at the mention of his cousin. "We've been writing back and force since I came here," he said. "I've gone to see her a few times over the last 7 years."

"Does she know you're…" Xavier started to ask already knowing the answer.

Scott let out a sigh. "She knows I'm a mutant," he said, "she was with me when my power first manifested. What is this about Professor?"

"I was just in Cerebro, Scott. I detected a mutant in California just now coming into her powers. Scott it's your cousin, Buffy." Scott's jaw dropped at the revelation that Buffy was a mutant. He was unsure what to say. "With your consent I would like to offer her a scholarship to come here. It might help her parents if you went with me to talk to her."

Scott nodded. "Of course, Professor. I would be more than happy to see her with you," he said. He wondered how his aunt and uncle would take the discussion that their only daughter was a mutant.

3 Days Later – Los Angeles, California

Scott drove the rental car up to the front of the Summers' home in Los Angeles. He got Xavier's wheelchair out of the back and helped the Professor in to it as he looked nervously at the house. He walked beside the Professor towards the front door wondering what he would say to Buffy, Joyce and Hank.

Xavier looked towards Scott. "It will be alright Scott," he said trying to comfort the man next to him.

"I know Professor. But I still can't help being a little nervous and anxious. This is not something I would have ever wanted for Buffy," Scott said,

Just then the front door opened and Buffy came running out and barreled into Scott as she flung her arms around him in a massive bear hug. "Scotty this is a wonderful surprise," she said, smiling.

Scott winced at the strength of the embrace as he glanced toward Xavier for a moment. "Buffy can't breathe," he said as he wondered what Buffy's mutation was. It was something that he had forgotten to ask the Professor.

Buffy smiled meekly. "Sorry," she said as she let Scott go. "Guess all those cheerleading practices really improved my strength." She looked from Scott to Xavier and then back to Scott with curiosity. "Who's your friend Scotty?"

Xavier extended his hand and Buffy shook it. "Charles Xavier," he said.

Buffy's eyes went wide with realization. She knew who Charles Xavier was from Scott's letters over the last seven years. "You run the school that Scotty went to after …" she said.

"Yes," Xavier said with a nod, "after his mutation first revealed itself. But I'm here to talk to you and your parents. Scott has talked me into graciously offering you a full scholarship to attend my school."

Buffy looked at Scott and smiled. "You did?" she asked. She was thrilled at the prospect of going to the same school her cousin had gone to.

Scott looked at Xavier remembering their conversation on the way there. They had agreed it might go over better if Scott had been the one to get Buffy accepted. "Yeah Squirt," he said. "Why don't you run inside and tell Aunt Joyce and Uncle Hank we're here."

Buffy nodded and ran back into the house.

Scott projected towards the Professor, knowing that the telepath could hear his thoughts. ~Professor, what is her mutation? You didn't say and I never thought to ask.~

~She is cognitive,~ Xavier projected as he glanced at Scott. ~She can see the past and the future.~

~So the strength and speed she demonstrated was definitely not her mutation?~ Scott projected back to Xavier as he thought about the bear hug that Buffy had just given him.

~No. And I don't understand it. Mutants generally do not have multiple gifts. And the ones that do develop them over time. ~ Xavier projected back with a shake of his head. ~She is just now coming into her powers and should not have developed a second so soon. I will have to run some tests. She may be a class five.~

~A class five?~ Scott projected back shocked to think of his cousin possibly being one of the most powerful mutants on the planet.

~Possible, yes.~

Scott and Xavier made their way inside the house to find Joyce, Hank and Buffy waiting for them.

"Hello, nephew," Hank said as he held out his hand and Scott took it and gave his Uncle a hearty handshake.

"Hello, Uncle Hank," Scott said before turning towards Joyce and pulling her into a warm inviting hug. "Hello, Aunt Joyce."

"How have you been, Scott?" Joyce asked.

"I've been good," Scott said with a smile. "Let me introduce you to Charles Xavier, the headmaster and founder for Xavier's School for Gifted Youngsters."

"It is a pleasure to meet you. Scott has told me a lot about the both of you," Xavier said.

Joyce smiled. "All good I hope."

"All good," said Xavier with a smile.

"So what brings you with my nephew?" asked Hank.

Xavier looked to Scott who nodded. "Uncle I have talked Professor Xavier in to allowing Buffy into his school on a full scholarship as a personal favor to me," Scott said as Hank and Joyce looked at each other with astonishment. They had both wanted to send Buffy to private school but had been unable to afford it.

"Mom, Dad can I go?" Buffy asked still quite excited at the prospect of seeing the school that Scott had went to and now taught at.

Hank and Joyce looked at each other and then politely excused themselves to talk privately about the possibility of sending Buffy to the school.

"So Scotty," said Buffy after her parents had walked out of the room. "Tell me did you like the school when you went there?"

"Yes, Squirt, I did," Scott said as he smiled at Buffy. "And you will too."

"Indeed. You will make an excellent student and I can even help teach you to control your mutation." Xavier said.

Buffy blinked in shock at the revelation. She was a mutant? "Mutation? You mean I'm like Scotty?" she asked.

Xavier nodded as he rolled over to her. "You are a mutant, yes," he said. "Have you been seeing things before they happen?"

"Yes," said Buffy as she looked at Professor Xavier. "The other day I was walking home from school when I saw this kid getting hit by a car. Then the next thing I knew I saw the same kid coming down the sidewalk. I went and stopped him before he could enter the street and get hit. There have been other times that's happened where I would see things before they happened, and they are coming more and more frequently now."

"Much as I expected," said Xavier with a nod. "I can help you to control your mutation and then to eventually be able to call it on demand."

Joyce and Hank reentered the living room and approached Scott, Xavier and Buffy with a serious look on their faces. Buffy was worried they would say no that she couldn't go to the school Scott had gone to. "We've discussed it," said Joyce. "If Buffy wants to go we'll let her. For us it's kind of a dream come true. We would love to have been able to send her to a private school, but have been unable to afford it. But it's up to you, sweetheart. If you don't want to go we're not going to make you."

Buffy smiled and hugged Joyce and then Hank. "I want to go," she said excitedly. "Thank you mom, dad."

"Then I will head back to the school and prepare for Buffy's arrival," said Xavier. "Scott you should stay and bring Buffy say in a week. That way she has time to say goodbye to her friends. And you can iron out details with your Aunt and Uncle."

"Of course, Professor," Scott said.

One Week Later in Los Angeles, California

Merrick arrived at Hemery High School to find the Slayer he had been assigned. A teenager who had somehow slipped through the cracks and had not been trained.

"Yes, sir, can I help you?" asked the school secretary as Merrick stepped into the office.

"I am looking for Buffy Summers," Merrick said. Through the Devon Coven, the Watcher's Council had been given a description and the name of the Slayer. Yet he did not know where to find her. "I am with the University of California, Berkley. I was sent to see about offering her a scholarship to attend after she graduates." He produced an ID that showed that he supposedly was who he said he was.

The secretary pulled up Buffy's file and shook her head. "I'm sorry, Mr. Merrick. Miss Summers has been removed from enrollment in our school."

Merrick nodded thanking the secretary and left. He used a few contacts and found out that Hank and Joyce Summers had filed for divorce and that Joyce Summers was moving to Sunnydale, California to open up her own art gallery.

Across the country in Westchester County, New York

Scott was driving the car down the road towards the mansion that served as the home of Xavier's School for Gifted Youngsters. "So Squirt are you nervous?" he asked glancing briefly at his cousin.

"A little," said Buffy. "Will there be others there like me?"

"Do you mean a mutant or with your mutation?" Scott asked.

"My mutation. I know from what you said that there are other mutants that attend the school," Buffy said.

Scott nodded and glanced at Buffy again as he smiled. "There are other cognitives in the world, yes. But there won't be another cognitive there," he said.

"How will Professor Xavier help me to control it?" asked Buffy, she was curious on how he would be able to do it.

"He is telepathic," Scott told her, "he can help you to build the mental walls you need to block out your power from overwhelming you."

Buffy looked out the windshield astonished at the building in front of her as they drove towards the mansion. "Wow," she said. "That place is big."

"There is five floors," Scott said. "Three are above ground and two below ground. The classrooms and living quarters are all above ground. Unless you get sick there is very little reason you will go into the sublevels. Our medical center is in the sublevels."

"I don't like hospitals anyways," said Buffy. Ever since she had watched her cousin, and Scott's sister, Celia die she had refused to step in another hospital.

"You still miss her," Scott said as he too remembered Celia.

Buffy looked at her cousin and nodded. "I do," she said. "Just as I know you do."

"I do," Scott said as he glanced at Buffy and smiled. "But at least we still have each other."

"Yeah," Buffy said.

Scott parked the car at the front entrance to the mansion. "Here we are," he said as they got out and Scott grabbed Buffy's luggage. "Come on Squirt."

Inside they found Ororo Monro and Jean Grey waiting for them in the foyer. "Buffy, this is Ororo Munroe and Jean Grey," Scott said in introduction. "They are two of the professors here and good friends."

Buffy smiled. "Hi," she said. She remembered that Scott had mentioned in the letters he had written her over the last few years, that Jean was his girlfriend. "It's nice to meet you both, especially you Jean. Scott has told me a lot about you in his letters."

"All good I hope," said Jean with a smile.

"All good," said Buffy.

"Hi, Buffy. Want to come with Scott and me on a little trip?" Ororo asked.

Scott frowned. "Trip?" he asked. They had just got in and now they were being asked to go somewhere.

Jean nodded. "Yes, the Professor wants you and Ororo to track a mutant," she said. "He thinks Buffy's mutation could be of use."

Scott sighed and nodded. "Okay."