A/N: Well, first this is obviously AU. It was based off of a roleplay that I do for Family Ties. By the way, if anyone likes to roleplay I am in need of an Elyse, Steven, maybe Mallory (not sure), Steven and Andy. Or even a Ned! Oh, I would love you forever! Ned's a small character, but still lol. PM me or surprise me, whichever! Anyway... my account is alex. , just putting that out there. And it is on Instagram. ANYWAY! Onto the story! And I know this is a crossover but I'm putting it on the BTTF archive because I know more people will see it.

Chapter One

It was November of 1985. 17 year old Alex P. Keaton walked up to the house, suitcase in hand. He couldn't believe it. He felt betrayed by his whole family, with them not telling him he was adopted.

"We didn't want to tell you because we thought you were happy here." His mother had tears in her eyes. Alex had paid no heed.

"I still had the right to know. I can't believe you've lied to me all these years!"

He had found out while snooping with his sister-well, not blood-related sister anyway-in his parent's bedroom.

"What's this?" Mallory picked up a box. She opened it and went through it. Alex looked over at her. Both of the eldest Keaton children had a sneaking suspension that Alex wasn't a Keaton by blood, and they finally decided to go find out while their parents were out of the house. "Oh my God...Alex!"

Alex snatched the box from her and looked it over. "Certificate of Adoption?" he furrowed his eyebrows.

"I knew it...!" Mallory exclaimed. "I so knew it!"

Alex stared at the front door before he raised a hand to knock on it. It was three, quiet knocks. Biting his lip, the young man waited for the door to open. When it did, a young man, looking exactly like him, stood in the doorway. He had his hair spiked a little and wore a simple white t-shirt and jeans. He was barefoot. His eyes were the same shade of blue as Alex's.

"Ah, hey... I'm guessing you're Alex, huh?" he rubbed the back of his neck.

"Yeah. Alex P. Keaton." The young republican held out his hand. The other boy took it.

"Marty McFly." He shook Alex's hand and then stepped to the side, letting the identical teen inside. Alex looked around.

"Nice."

"Thanks. I'm starting to like it." Marty shut the door. He looked at Alex. "So, you're my twin."

"Yeah, I am..." Alex nodded.

"So, not only am I adopted... I have a twin brother..." Alex gaped at the picture.

"Wow... I hope he's not just like you." Mallory teased. Alex glared.

"Nice to finally meet you," Marty smiled.

"You too..."

The twins stood there, in silence, for a few moments before Marty shook his head.

"Sorry, I'll show you to the guest room."

"Thanks..."

The McFly boy walked to the back of the house and opened the door across from another. Alex had followed him, his suitcase in his hand. He walked into the room and looked around.

"Need any help?"

"Huh?" Alex looked at his twin. "Oh, no. Just my clothes, toothbrush, hairbrush... Nothing special." At this, Marty nodded. "So where is everyone anyway?"

"Well, Mom and Dad are out to lunch, Dave is at the office and Linda is on a lunch date."

"Dave and Linda."

"My older siblings. Well...I guess our older siblings."

"Yeah,"

The awkwardness hung in the air like a thick blanket. Marty shuffled from foot to foot while Alex unpacked. Finally, the Keaton spoke.

"So, tell me about yourself. I think I need to learn about my twin." He smiled a little.

"Right. Yeah. Ah, well... I'm in a band, I play guitar... I have a girlfriend..."

"What's your band called?"

"The Pinheads."

Alex furrowed his eyebrows. Who the hell named a band The Pinheads?

"And your girlfriend? What's she like?"

At this, Alex could see his twin's face light up.

"Her name's Jennifer. She's beautiful. Absolutely beautiful." He grinned and took his wallet out of his back pocket and crossed over to his brother. "Here. This is her." he took out a picture of a young woman with light brown hair and chocolate brown eyes. She wore a simple pink blouse and jeans and was smiling.

"God, Marty, she's gorgeous." Alex took the picture and looked at it. Marty slowly reached for it after a minute.

"Okay, you got your fill." He teased. "Quit staring."

Alex laughed quietly, going over to the closet. Marty looked at his clothes.

"So, all you wear are suits and ties?" he looked at him. Alex grabbed a few hangers and nodded.

"Yeah, why?"

"Well... when I found out I had a twin I didn't picture him dressing so sharp."

Alex walked back over to the suitcase. "You couldn't tell from what I'm wearing now?" he motioned to the suit he was wearing, which was a dark blue tie, beige shirt, a maroon blazer, khakis and dress shoes. He then set the hangers down.

"Well, I thought you just... Dressed to impress today." The McFly laughed quietly.

"Sorry to disappoint you." Alex joked. Marty shrugged. "So, what's the family like?"

"Mom's a simple, stay at home mom. Dad's a writer," Marty had to think. He was still getting adjusted to this version of his family. He was still used to the alcoholic mother and wimpy father. Plus the loser brother and the desperate sister. "Dave works in an office, and Linda's a boy magnet." He still couldn't believe it, honestly. He still expected his mother to break out the vodka at dinner. And lunch. And breakfast.

"Sounds like a pretty normal family..." Alex sighed quietly. Marty scoffed inwardly.

He has no idea... he thought to himself. "So, what's your family like?"

"Well... Um... Elyse is an architect... Steven works at a public broadcasting station... Mallory's two grades below me in high school, and Jennifer's in elementary school still. She's nine."

"Elyse and Steven? Those your parents?"

"...Yes..." Alex found it hard to say that. After all, he felt like he had been lied to all those years, and he really wasn't a Keaton after all... And the thought stung him. It stung him like thousands of hornets hitting him repeatedly. He felt like a pariah after he had found out the news, and he had to get out of there. So he dug for the number of his blood relatives and called them, and explained who he was. The woman, he assumed it was the mother, was sobbing on the other side of the line. But they were obviously tears of joy. They talked for hours almost, getting to know each other and then he and his birth mother made plans for him to fly out there to meet. With the money he had saved up, Alex bought a round way ticket and left the day after.

"Why're you calling them by their first names?"

"Because they lied to me and I'm not happy with them." Angrily, Alex shoved his clothes onto the hangers and hung them up, almost slamming the closet door.

"Ah... Right..." Marty rubbed the back of his neck. "They probably didn't have the heart to tell you. I mean, you have to think about things like that." The McFly shrugged. "After all, you are their son."

"Not really..."

"Alex..."

"Look, Marty..." Alex shook his head, leaning on the wall. "It's been great to meet you and all but... Could I be alone for a little bit? Please?"

"Yeah. Sure." Marty walked over to the door and opened it. He looked at his twin brother. "Yell if you need anything, alright?"

"Yeah..." Alex said quietly, and with that, Marty left.