Summary: Receiving a call that his daughter is missing, Tony Stark quickly leaps into action to help find his daughter. After learning that she's been fighting a war of her own, Tony learns just how special Buffy Summers-Stark and her friends really are.

Disclaimer: I don't own Buffy or Marvel

A/N: I want to thank my beta reader for helping me with this story.

Tony Stark is Buffy's biological father.

In this story Buffy's full name is Buffy Anne Summers-Stark, she just uses the last name Summers to stay out the public eye.

This story will be set in modern day. With an ambiguous timeline for the Marvel side and mostly following season 3 mixed with elements of the Boom Studios reboot for the Buffy side.

Thor is an actual god and has a history with a past Slayer in this story.

Magic will be a bit different than shown in Buffy and Marvel.

In this story I'm imagining Ross Lynch as Xander Harris and KJ Apa as the character of Pike (the first person Buffy ever saved, the first person she told she was The Slayer.

It was a quiet night in the city of Malibu; the moon hung high in the sky, reflecting beautifully on the water of the pacific ocean as a few dolphins swam near a beach side mansion owned by the one and only Tony Stark; Tony along with his boyfriend/fellow superhero, Steve Rogers entered the luxurious home; the latter was carrying a couple boxes of pizza while the former was looking through upgrade designs he could make to his teammates' super suits.

"Just sit those on the counter." Tony said when he finally put his StarkPhone away. "Don't wanna overwork a vintage model." He added with a teasing grin.

"Oh, I'm vintage now?" Steve replied with a teasing grin of his own as he looked at his boyfriend.

"Hey, they don't make 'em like they used to." Stark said with a playfulness to his tone as he winked at the blond super soldier.

"Mr. Stark." JARVIS interrupted. "Call for you from Joyce Summers"

"I'll take that," Tony replied, all the playfulness suddenly gone from his tone. He took his phone out and answered. "Hey Joyce! How's it going, been a while?"

Steve frowned at the sudden change in his boyfriend's attitude. Who was this Joyce Summers person and why did she have such a drastic effect on Tony's mood?

"Hi Tony." Joyce's voice was heavy with sadness and desperation. "It's about Buffy, we got in a terrible fight, and the police were looking for her… Tony, she ran away." Joyce confessed.

The billionaire's eyes went wide upon hearing that his daughter was in some kind of trouble with the police and that she had run away, he immediately went into protective mode. "W-what happened?" He asked, trying to keep the building panic from his voice.

"We got in a really bad fight, oh God I said the most horrible thing to her." Joyce sounded like she was on the verge of tears herself.

"We'll talk about that when I get to your place." Stark said, trying his best to not let his panic over take him. "Now why were the police looking for her?" He asked as JARVIS pulled up the police file on his StarkPhone. "Never mind, I have the police file."

"Okay." Joyce said quietly.

"Okay, when was the last time you saw her?" Tony asked tersely, holding back his building anger and frustration. "What was she wearing, did she take anything with her? Anything you remember helps, Joyce."

"I don't remember everything," Joyce admitted, accustomed enough to Tony not to be overwhelmed by the barrage of questions. "I know she took a lot of clothes with her. Maybe enough for a couple of weeks… Tony, it's been a month."

It took all the control Tony had not to let loose on Joyce, his daughter had been missing for five days and he's only now finding out about it. "A month, really Joyce, our daughter's been missing for a month and you're telling me this now?!" Tony exclaimed, from his tone it was clear that his anger was clashing with his panic.

"I didn't think she'd be gone this long. I just thought she would go stay with a friend until she cooled off." Joyce said before she and Tony said their goodbyes and hung up.

Tony looked as pale as a ghost and spoke with a trembling voice as he told JARVIS to have the rest of the team gather in the living room, and had the AI begin a search in California and its neighboring states for his eldest child.

Steve looked at his boyfriend with a furrowed brow. "What was that about?"

"There's something I need to tell you, and I'm not sure how you're gonna react." Tony said, running a nervous hand through his dark brown hair.

The blond super soldier frowned at that. "Tony, what's going on, what was all that about?"

"Peter isn't my only kid… I have a seventeen year old daughter." Tony admitted to his boyfriend, the nervousness was quite noticeable in his voice.

"You have a daughter?" Steve asked, confused by what the multibillionaire just revealed to him.

Tony let out a soft sigh before he began revealing how he ended up with a teenage daughter, "Only Happy, Rhodey, and Pepper know about Buffy and Joyce. We kept it that way to protect them. Now I'm adding you and the team to that list of people." Tony took a seat in the living room before continuing his story.

"When I was in my last year at MIT I went to a party with a friend of mine, Joyce Summers. She had just gone through a really bad break up with her boyfriend and she was in a bad place. So, we both ended up drinking; I mean, it was college. Well one thing led to another, and we had a one night stand. Anyway, Joyce was twenty at the time, so when she found out she was pregnant, she told me I was the only one she had been with. A few months after that she ended up getting back together with Hank." Tony began running his hands over his face and through his hair, before taking a deep breath and letting it out slowly. "Hank and Joyce ended up getting married, and Hank took Joyce's last name. He treated Buffy like she was his own, so we ended up co-parenting until Buffy was fifteen. That's when Hank and Joyce got divorced… after that Buffy became distant, she barely calls or texts as much as she used to, and now she's missing. Joyce said she ran away, and the police were looking at Buffy as a murder suspect. Which is complete bullshit, Buffy's a good kid, she would never hurt anyone."

Steve pulled Tony into a hug seeing that tears were building in his eyes. "It's okay baby, we'll find her I promise." Steve told him, silently swearing on his mother's grave they'd find Tony's daughter.

XxX

The next morning in the city of Los Angeles, a somber Buffy Summers made her way through the streets, being careful to avoid running into her former stepfather. She's been in L.A. for a month now and she's been fighting every urge she's had to go home, or go to Tony. She kept telling herself that everyone was better off without her; she kept telling herself that she only brought pain and destruction wherever she went.

Her first watcher, Merrick wouldn't be dead if it wasn't for her. Hemery High School's gym wouldn't have burned down if it wasn't for her. Her mother and Hank wouldn't have gotten divorced if it wasn't for her. Willow and Xander's friend Jessie wouldn't have died if she had gotten to them faster. Her friends wouldn't have put themselves in harm's way if they had never met her. Angel wouldn't have lost his soul if it wasn't for her. Jenny Calendar wouldn't be dead if it wasn't for her. Her friends wouldn't have been hurt and Kendra wouldn't be dead if they weren't fighting her fight. Giles' wouldn't have been tortured if it wasn't for her. Angel wouldn't be dead if it wasn't for her.

Those were the thoughts that were on a constant loop in the young blonde's head as she stoically waited on tables at "Helen's", a diner owned by her friend/e Pike's aunt. Buffy had gotten lucky enough that Pike was still in town when she showed up after leaving Sunnydale, and even luckier that he let her crash on his couch.

"Anything else?" Buffy asked, taking out an order pad occupied by two sleazy truckers. The grieving Slayer kept her features calm while ignoring the lecherous gaze the two men were directing at her.

"That'll do us, peaches." One of the truckers said with a smirk on his face as he eyed Buffy up and down; clearly having less than wholesome thoughts about the young blonde.

She tore off their bill and put it on the table. "You can pay at the counter."

"Sure you don't want me to work it off for you?" The sleazy trucker asked, wearing a lustful smirk as he subtly gave his lap a light pat and earning a chuckle from his friend

With a roll of her green eyes, Buffy walked away from the table, only for one of the truckers to swat her butt. Causing the young blonde to stop in her tracks. The two men just laughed as if it was the funniest thing in the world.

For a moment, every cell in her being was screaming for her to fight, but she took a deep breath and thought better of doing anything about it before carrying on with work.

She walked up to another table where a rather young and bubbly couple, Rickie and Lily, were sitting. They were so enraptured with each other that they didn't even notice Buffy until she cleared her throat to get their attention. "You guys ready?"

Rickie gave a short nod but was still focused on his girlfriend. "Yeah, I think we're good, um…" He looked to see Buffy's name tag. "...Anne."

Buffy briefly glanced at the couple before looking down at her order pad. "What can I get for you?" She asked, ignoring the feeling that she had seen Lily somewhere before.

"Well, okay…" Rickie said as he dumped a bunch of change onto the table, amounting to no more than a couple of dollars. "What can we get with this?"

"Um…" The Slayer trailed off, already calculating the math in her head.

Wearing a small pout, Lily asked if they could get cake, but Rickie ordered pie with the excuse that they had to eat healthy. Lily looked at Rickie and spoke quietly. "We shouldn't have spent all our money."

The young man just smiled at his girlfriend. "Come on babe, it was worth it," He said and Lily met Rickie's smile with one of her own. The couple looked up at Buffy and held out their forearms. "Hey check this out." The dark haired teen said with a proud smile.

Buffy took in the sight of the couple's forearms and saw they each had a tattoo of half of a heart with a ribbon across it. On their respective halves of the ribbon they had the other's name tattooed. Buffy flashed them a weak smile to the couple. "It's nice… it's nice and, uh, permanent."

Rickie wore a smile as he looked at his girlfriend with nothing but love in his dark brown eyes. "Yeah, forever." He said before pecking her cheek and putting his arm around her. "I mean, that's the whole point."

Lily looked at him and smiled sweetly; neither of them took notice of the sadness on Buffy's face. A moment later, the blondes locked eyes and there was a spark of recognition for both of them

"Hey do I know you?" Lily asked with a friendly smile and curious tone.

Buffy looked away, willing herself not to make eye contact with the other blonde. "I don't think so."

"Really, where ya from?" Lily asked with a curious brow raised.

"I'll go get your pie." The Slayer said before she took off, avoiding the issue and took off.

XxX

Later that morning in Sunnydale, Joyce was calling Buffy's phone for the thousandth time that month hoping that this would be the time her daughter answered. Sadly the call went straight to voicemail, just as it had done since the night Buffy left.

Letting out a loud sigh of frustration, Joyce threw her phone down on the couch and buried her face in her hands as she sat down.

A knock on the front door startled Joyce, shaking off her momentary fright Joyce got up and quickly made her way to the door. She had to hide her disappointment when she opened the door and was greeted by Buffy's friends.

"Hi, Mrs. Summers." Willow said with a polite but shy wave while the others gave their own variation of hello and Joyce greeted them in return before inviting them inside.

"How are you doing?" Giles asked as everyone took seats around the living room.

"Not great honestly. I'm trying to stay strong, just hoping Buffy will call or text or post something but it's just so hard." Joyce admitted, the woman's eyes held stress, exhaustion, and deep regret.

"Hey now, you gotta keep your head up, Buffy's gonna come back any day now." Xander said with an optimistic tone to his voice just as someone knocked on the door. Hopeful looks graced everyone's faces, even Oz's face, when Joyce got up to answer the door.

Upon answering the door, Joyce couldn't help feeling a little disappointed when it wasn't Buffy at the door, but her disappointment was overshadowed with gratitude and surprise upon seeing not only Tony standing on the porch but Thor and Captain America too.

Joyce and Tony immediately hugged each other, taking comfort in each other the only way that two parents can when their child is missing. "Tony, I really screwed up. It's all my fault." Joyce's voice was accompanied by an unsteady breath as she buried her face in the nape of her best friend's neck to hide the tears that filled her eyes.

"It's okay Joyce, we're gonna find her." Tony said, taking a step away from Joyce but continuing to hold her shoulders. "What happened, what could you have possibly said to make Buffy think she couldn't come?"

Joyce could feel her tears begin to fall as she quietly invited the three Avengers inside, and led the three men into the living room where Buffy's friends were still waiting.

Upon seeing three of the Avengers walk into their friend's living room, Willow and Xander's eyes went wide with shock and while equally surprised, Giles and Oz kept their calm exteriors. "Um w-w-what are the Avengers doing here?" Xander asked with awe in his voice.

"Tony is Buffy's biological father, he's here to help find her." Joyce revealed, her voice wavering as she wrung her hands together, refusing to look up from the floor.

"Yeah, and I need to know what happened and what's going on before I can do that." Tony said with a sigh. "Let's start with why Buffy decided she needed to run." He said as his eyes went to the mother of his eldest child.

"I told her that if she left that night to not bother coming back." Joyce's voice rang out in the silence even though she spoke barely above a whisper.

"What the hell is wrong with you, Joyce?!" The 36 year old superhero snapped. "Why the fuck would you to ever say that?!" Tony began his voice rising with every word he spoke.

"You weren't here, and she wouldn't talk to me Tony! She hasn't told me anything about what's been going on with her since we left L.A.! Then the police show up and say she killed someone, what am I supposed to think?" Once Joyce started her volume raised to match Tony's.

"YOU AND BUFFY CUT ME OFF FOR TWO YEARS!" Tony snapped, startling everyone. "FOR TWO YEARS, YOU SHOT ME DOWN EVERYTIME I TRIED TO PLAN A VISIT, BUFFY BARELY EVEN TALKS TO ME ANYMORE, SHE HASN'T EVEN MET HER BROTHER, OF COURSE I WASN'T HERE!" Stark ranted stunning everyone, his eyes filled with tears as he buried his face in Steve's shirt. "You're supposed to tell her everything will be okay and call me!" Tony said with exasperation as his volume lowered. "You're supposed to believe your daughter could never hurt anyone."

"Oh she could definitely hurt someone," Willow said quietly. Xander turned, giving her a look that clearly said 'really'.

"What do you mean by that?" Steve asked her quickly before either Tony or Joyce could begin yelling at or interrogating the young redhead.

"Oh well, um-, I mean-" Willow tried several times to find a way to explain what she meant without actually telling them anything.

Thor had been watching the older man who stood with the teens on the other side of the room from him. Upon hearing Willow's comment and subsequent floundering for an answer, he seemed to reach whatever conclusion he had been looking for. "She is a Slayer of old, is she not?" He asked seemingly out of the blue. "Which would make you a Watcher." He said to Giles, shocking the Englishman.

"Wha- how could you possibly know that?" Giles asked, too stunned to do anything other than confirm what was said with his question.

"You stand with a wolf and a witch. You're an older man who works with children instead of adults, and you seem worried that she ran. Not to mention that I and Loki fought alongside a Slayer centuries ago." The blond God of thunder said, as if it was the most normal thing in the world.

"You fought with a Slayer?" Willow asked, shocked that a God had fought with a Slayer.

"Yes, they are powerful warriors who shall be welcome in the halls of Valhalla." Thor said in his loud booming voice, with a smile spreading across his face.

Giles was stunned at this news, here was an actual God standing before him talking about Slayers and fighting with one. He couldn't believe the incredible turn this day had taken, not only were there three Avengers standing in front of him, but one of them was the father of his Slayer and another speaking of the Slayer line with high regard.

Confusion spread over Steve and Tony's face as they took in what was just said. "Thor, buddy, what the hell are you talking about?" Stark asked, making his confusion known.

Giles cleared his throat before removing his glasses. "Mr. Stark, you may want to have a seat." He said, already knowing this would be a difficult topic to explain.

A/N: If you like this story, leave a comment with your thoughts about it. Please feel free to leave any predictions and suggestions you may have.