I do not own the Avengers or anything affiliated with them. I do own Ari. Enjoy!

It was a typical day in Stark Tower. Dr. Bruce Banner was in his lab, as usual, studying genes. The billionaire, Tony Stark himself, was keeping busy in his workshop. Natasha Romanoff and Clint Barton sparred while Thor, god of thunder, stood by; laughing at their impertinence. Meanwhile, Steve Rodgers tried to figure out how to use the TV remote.

The voice of JARVIS resonated throughout the entire building. "Commander Fury would like to have a word with you all in the command center immediately."

Dr. Banner let out an exasperated sigh at these words. He really didn't like to stop his work when he was in the middle of something. He dropped his pencil and reluctantly left his lab' looking over his shoulder to make sure he hadn't forgotten anything.

He was the last one to arrive. Nick Fury stood at the head of the table with a young woman he had never seen before. She was short, maybe five foot two at most, and looked to be in her early twenties. She wore jeans and a navy blue hoodie; her dark brown hair pulled back in a low ponytail. The girl looked nervous, scared even, as she glanced around the silent room.

"All right," Fury started. "The director thinks that you need another member on the team." He gestured to the girl standing next to him. It didn't seem like he was too happy about the new addition to the Avengers. "This, here, is Arianna-"

"It's Ari," the girl interrupted.

"Arianna Martin," Fury continued as if he was never interrupted in the first place. "A.K.A. Fathom… Now y'all play nice and get along." He left without another word.

"Is this some kind of joke?" Thor boomed. "She is nothing but a child!"

"Who're you calling a child, Barbie?" The girl snapped back.

Stark laughed at her remark. "I like this girl," he said. "Can we keep her?"

"What is a Barbie?" The Asgardian asked Agent Romanoff. The red-head rolled her eyes as he looked at her in confusion.

The super-soldier pushed his way around the two of them. "Steve Rodgers," he said, holding his hand out to the newcomer. "Welcome to the Avengers."

"Ari Martin," she replied as she shook his hand. "And thanks for welcoming me."

Ari turned to watch the rest of her new team attempt to explain to Thor what a Barbie is. Well, all but one. The dark-haired man stood in the corner of the room, seeming out of place. "Who's that in the corner?" She asked Steve.

"Dr. Bruce Banner," he answered. "But the rest of the world knows him as the Incredible Hulk."

She stared at the captain blankly. "Never heard of him."

Steve then lead Ari around the room, introducing her to each of her new comrades. He found it odd that she left the room without a word shortly after the introductions. He went after he with Dr. Banner following close behind. Banner, of course, was heading back to his lab. The super-soldier followed Ari to what seemed to be her quarters.

"Dude, stop following me," she said as she opened the door.

"Mind if I come in?" Steve asked nonchalantly. She shrugged her shoulders in response and he entered after her.

The room was fairly empty except for a bed, nightstand, dresser, and bookcase. The walls were bare and notebooks were strewn all across the hard wood floor. Steve bent over to pick one up and flipped through it. He realized that they weren't notebooks, but sketchbooks. Each page was filled with some sort of complex, detailed drawing. One page fell out onto the floor. He picked it up. It was a drawing of a girl with black wings falling out of the sky. A falling angel, perhaps? The detail was incredible. He couldn't help but notice the resemblance between this girl and Ari.

"What are you doing?" Steve looked up at the sound of Ari's voice.

"I was just-"

"Give me that!" She took the sketchbook out of his hands and picked up the rest before he could invade any more of her privacy.

"What is it you can do, exactly?" Steve asked her as she put her sketchbooks into one of the drawers of her dresser. Ari didn't answer. Steve thought it would be best to leave her on her own for a while and left without a sound. She didn't know he was gone until she turned around.

Ari yawned. The long trip to New York City had left her drained and exhausted. She practically threw herself down on the bed and attempted to fall asleep.

She opened her eyes and looked at the alarm clock that rested on her nightstand. She had only slept for twenty minutes. As Ari laid her head back down on the pillow, she became restless. She had to get up and walk around before she started bouncing off the walls.

Ari Sat back up in bed, fixed her hair quickly, and let her socked feet lead the way. She wandered around the massive tower, using the stairs rather than the elevator, until something caught her eye. On the other side of the glass door was Dr. Banner. Obviously, she had found his lab.

"What are you working on?" She asked as she entered.

Dr. Banner turned around, surprised to see the young new member of the Avengers standing in the middle of his laboratory. There was something about her that made him uneasy. He didn't know what, but he knew to trust his gut when it came to things like this.

"I'm studying genetic mutations," he answered he question at last.

"Cool," she said. "Want another sample to test?" The doctor just stared at her, confused. Ari walked over to a table with an expensive looking microscope sitting on it. "Are these slides clean?" She asked, holding one up. Banner nodded. "What about this?" She held up and extremely sharp-looking scalpel. Again, he nodded warily.

Before he could stop her, Ari poked her index finger with the tip of the scalpel until she bled. She picked up a clean slide and let a single drop of blood fall onto it. She set it down on the table and brought her finger to her lips in order to stop the bleeding.

"So, I'm guessing you're here because you're somehow genetically altered?" Banner asked her.

"That would be a good guess."

He ignored Ari's blunt answer. "If you don't mind my asking, how old are you, exactly?"

"Twenty-six," she answered quickly. Dr. Banner raised an eyebrow at her. She rolled her eyes. "Twenty-two."

"Stop lying to me, Ms. Martin."

She chewed on the inside of her cheek. Finally, Ari said, "I'm nineteen."

Banner ran a hand through his already messy, dark hair. "Why would Fury let a kid like you put herself in danger like this?"

"He was going to put me in when I was twenty-one anyways," Ari replied with a shrug.

"What do you mean?"

She hesitated. "SHIELD has been training me since I was thirteen."

"So, you're basically just another one of SHIELD's super-soldiers?"

"Basically," Ari replied. "So, Dr. Banner, now that I've told you part of my story, what's yours?"

"When I'm angry I turn into a giant green monster. There's not much else to it."

"And you're studying genetic mutations in hope that you'll find a way to get rid of the Hulk?"

Banner said nothing and went back to his work. "What are you doing here anyways?"

"Like Fury said, the director wanted another member on the team."

He laughed a little. "I meant, what are you doing in my lab?"

"Oh." Ari smiled nervously. Banner couldn't help but notice that her entire face lit up when she did. "I just wanted to know what you were working on… I've always found science interesting."

Banner looked back down at his work. When he looked up again, Ari was gone. There was something intriguing about her. The uneasiness that came when she had entered the lab had left as soon as she began to open up to him.

Curiosity got the best of him. He went over to the lab table with the microscope on it. The slide with Ari's blood on it sat next to the microscope along with the bloody scalpel. Banner carefully picked up the slide and put it under the microscope. He bent down and looked through the lens. Once he had focused in on the blood cells, he stood back up. Not only did he see the round, circular human blood cells, but something else as well. The oval blood cells of a bird.

"She's part bird?" Dr. Banner asked out loud, perplexed. "That doesn't make any sense!"

He bent back down to look at the sample again; to make sure he wasn't just seeing things or going insane. The bird cells were still present amongst the human cells.

Banner took off his black wire-framed glasses and practically threw them down on the table as he ran out of the laboratory. He didn't know why, but he knew that he needed to get some answers out of Ari.