AN: Just wondered about who Stella's family really is. And this is how I imagined her learning to care (like she does for Mac) and learning responsibility.

This will remain a oneshot. All my thoughts for continuing this go very, very dark. I don't know if that's where I want to take this. ;)

Disclaimer: Characters and situations don't belong to me. Though the OC is purely my imagination.

Stella's Sister

"Well, Stella, I don't just want to bring up anyone to replace Jane as head of the DNA lab," Mac was saying, as the two walked the hall of the crime lab. Stella was shaking her head, "Mac, you have to bring in someone; and someone good – Jane will be on maternity leave for nearly 3 months!"

"Exactly," Mac's tone was even, not registering Stella's irritation, "Which is why I'm going to need your help bringing her here. She's not much for a city like New York."

"Too big?" Stella inquired. "No," said Mac, "Too unfriendly."

Stella groaned, "You're not suggesting that Baltimore, Maryland is friendlier than New York City?" Mac grinned.

"She'll never agree to this, Mac. She's entirely overqualified, and I doubt she'll want to come back to New York." Stella smiled slowly, and added, "But it would be nice to see her again."

"Is this you agreeing to help me?" Mac asked, cheekily. Stella's smile grew wide, before fading quickly, causing Mac a bit of unease, "What is it Stella?"

"I don't think anyone needs to know how we know her," Stella said cautiously.

Mac nodded, and patted her arm in what he hoped was a reassuring manner, "No one needs to know she's your foster sister."

"You really think Ally will agree to come back to New York?" Stella asked quietly, raising her eyebrows at the floor.

"Sure she will. Just don't call her Ally at work."

It was now August, and Allanah James stepped onto the busy, rush-hour platform at Grand Central Station. Her friends at Johns Hopkins thought her slightly crazy for taking the train to New York City when she could just fly. But to Ally, it was just another adventure to add to her list. The next train ride, she decided, was going to be across Canada, stopping along the way to hike and take pictures. She flipped her waist-length golden-brown hair up into a quick bun, and attempted to haul her suitcase from the stairs on the train. Of course, she over packed the large suitcase, and she would have sworn – if anyone was listening – that it weighed more than her. "Come on, you damn suitcase," Ally swore at the bag.

"Now really, Ally, is that any way to treat luggage?" Ally heard the quip and smiled to herself. "Now really, Mac, is that any way to treat a lady?" Turning her head she grinned up at him, and said, "The least you could is help!"

Mac grabbed the handle and heaved the stubborn suitcase off of the train, and started rolling it away from the car. Ally grabbed her overnight bag and followed suit. "So, Mac, where's the evening star?"

Mac chuckled, "I don't know how you get away with calling her that." Ally smiled, "It is truly what her name means: Stella – "star", Bonasera – "good evening". She can't fault me for that!"

Mac laughed at that, "She's at work until at least 7, which is why I'm here picking you up. Though, I would have expected to see you at JFK or LaGuardia – not Grand Central Station," Mac looked at her quizzically.

Ally's eyes twinkled, "Mac, you should know by now that I'm always up for the adventure. I flew away from New York; just thought I'd try something different on the way back." Mac laughed again, "You make it sound like a vacation. You haven't been back to New York in ten years."

Ally sighed, not responding, and in her silence, agreeing with Mac. They silently made their way to Mac's car, while Ally thought about her last few minutes in New York…

Stella walked with her to the gate at JFK. They weren't really talking, but Ally knew Stella was upset at her leaving. But she had to go, had to get out of New York. She'd been there too long, and her nerves were wearing thin. She'd found a job as a molecular biologist after she graduated college at 18, something Stella would never let her forget. Stella had been bragging constantly about her genius sister and her ability to match wits with 25-year-olds. Ally had never thanked her properly, she thought as they heard the final boarding call. What Ally never said to Stella, until this moment, was whispered between the closest of confidants, "Thanks for being my family."

Mac opened the door to Stella's apartment, and led Ally into a very comfortable living room. Ally took a deep breath, and realized that, even though she'd never been here before, it was home. Mac gave her a moment to glance around and said, "Second bedroom is down this hall on the right. Stella said that would be yours for the three months."

Ally smiled. The first genuine smile she'd shown in nearly two years. Mac recognized the smile. He'd seen that smile when he and Stella had gone to help Ally celebrate graduating with her PhD from Johns Hopkins. Stella hadn't shut up the entire flight down to Baltimore about her Doctor-Sister, who – at only 25 – had become the youngest tenure-track genetics professor at Johns Hopkins.

Mac smiled back, "I'm glad you were able to convince them to let you take a sabbatical this semester." Ally outright laughed at this, as if this was the funniest thing she'd heard in a while. Mac still smiled, but cocked his head at her, again confused at her reaction. Ally responded after a minute, "Oh, Mac. You're too funny. They are not about to deny me much. I'm a huge admissions draw. You know, hyper-competitive, type-A's who want to show me up? Johns has had the pick of the litter these past two years. Besides, I'll be researching while I'm here; I promised I'd publish again before the year is out."

Mac shook his head, "Don't they think three articles per year is enough? What are you researching this time?" Ally shifted her eyes away from Mac, and tried to sound innocent, "Oh, you know… the use of DNA technologies in crime scene investigations."

"Doctor James." Mac's voice was almost a warning, but he knew her published papers were always something cutting edge, usually with an angle no one had thought of before. And he knew this because Stella was always shoving her publishings in front of him to read, not that he understood some of the more technical scientific and mathematical aspects. But Mac knew, just as Stella took care of him, he took care of her. Mac was the only one of Stella's friends who knew her real relationship to Ally.

Mac's phone rang, causing Ally to release the breath she'd been holding, waiting for Mac to scold her. Instead, he winked at her, and she laughed. This was the Mac Taylor she knew, though she wasn't sure how it was going to work at the lab. "Taylor. Uh-huh. Uh-huh. Yah…" Mac wandered into the kitchen, and Ally took this opportunity to take a good look around her sister's apartment.

She found a bookshelf and ran her fingers along the titles, ranging from Shakespeare to industry journals. She smiled as she noticed seven medical journals alongside the books; the seven she'd been published in these past two years. There were several pictures on the shelves, along with the books; some identical to the ones in her apartment in Baltimore.

She paused to look. Stella and Mac dressed to the nines holding champagne flutes, Stella and two others in CSI gear who she assumed were Danny and Sheldon based on previous descriptions, and Ally's personal favorite, the one she had framed on her nightstand: a picture of a young Stella with her arm thrown over a giddy and grinning 13-year-old girl in front of a run-down apartment in the Bronx.

Ally sighed happily, remembering that day. That was their first apartment on their own. Stella had turned 18 that year, joined the NYPD, and had won legal guardianship of Ally that sweltering Friday in June. Three days later, on Stella's encouragement, Ally had sat for her GED, and on that same encouragement, applied to NYU, later receiving a full scholarship.

"You know, Mac, it's a bit rude to stare," Ally said to the room. Mac had finished his call and had leaned up against the doorframe to watch her. He seemed genuinely surprised to have been caught. "How…?" Mac started to question, and shook his head.

"Stella said you were a bit psychic." Mac's face was amused and skeptical. She turned to face him and laughed, "I prefer 'perceptive', thanks."

"That was your 'star'," Mac said, meaning the phone call, "She's on her way here. You up for some take-out Chinese?"

Stella practically bounded up the stairs to her apartment. She was way too excited to walk. She hadn't seen Ally in two years. Throwing open the door, she could tell the Chinese take-out had beat her home. And there was laughter coming from the kitchen, which suddenly stopped when she slammed the door. Stella saw a flash of a green shirt before being thrown back two steps by the biggest bear hug she could remember.

Stella regained her footing, and hugged her sister with all her might. "Hey, baby girl. I'm here. It's okay." Stella repeated the long-familiar words to Ally, causing a tear to spill silently down the younger's face. Mac, who had been watching, turned away from the family gathering politely, but was still astounded at the outpouring of emotion from Stella, who was usually walled off to others.

"I missed you," came Ally's response. "I missed you too, Al, but we talk every week," Stella replied, pulling back from Ally's embrace, tucking errant hair back behind her ears. Ally laughed, "I know, I know. Come on, we've got Crab Rangoon, and Veggie Lo Mein. And you have to tell me what case you were on today…"

Please Reveiw!