T/W: mentions of self harm, underage sex, drugs, alcohol, thoughts of sucide, More to be added later in following chapters as needed. Story is my idea enabled by Sarah ( Sarah11650 ) who helps bring this story to life. Will be crossposted on the following sites under the following usernames:

AO3: Stephanie_M

Wattpad: Stephanie_M123

Can also find more information about me or how to connect to us please visit my profile. Everything is there.

Chapter One

Little Girl Lost

It's pouring rain on a cold New York night in November. The park is empty as even the occasional drifter has fled in search of shelter. A loud crack of thunder booms, and a flash of lightning illuminates the tiny brunette girl curled up on the park bench.

She had run away. Again. Only this time she knew she couldn't go back. She couldn't go anywhere. Her mother had hit her limit finding more Oxy in her jacket pocket, and there was no amount of pleading and explaining that would make her listen when she swore they weren't hers. She had left in just her zip up hoodie, trying to prove a point at the time by not taking the jacket with her.

She regretted that now as she lost feeling in her fingers and toes and realized she was completely soaked from head to toe. Cowering on the park bench she considered her limited options. Her sisters were out; they would probably try to have her arrested for drug possession. And Derek? He didn't want anything to do with her; not since she'd crashed his car a few weeks back while she was still using.

Her frail body shook violently in the cold and a small part of her wished she had taken the drugs; at least then she would be a different kind of numb. But she was sober now and it didn't matter. She figured she probably deserved what was happening to her. This was her karma for the mistakes she'd made, and she knew she had to accept it. There was nothing else she could do.

Minutes or maybe hours later, she can't tell, she's abruptly shaken awake. Before she can stop herself she bursts into tears realizing it is the police. They ask her what her name is and where her home is.

"Amelia Shepherd."

She rasps out, before blurting out Mark's address, hoping that her other big brother might take pity on her and let her hide out with him for a while. Just until she has another plan.

Half asleep, dressed in only a pair of loose grey sweatpants, a young twenty-something Mark Sloan stumbles to his door, rubbing his face and yawning loudly. He opens it just as he hears another knock and his eyes grow wide at the sight of the police at his door at 3AM.

Before he can process that alarming detail, his shock shifts to worry as he catches a glimpse of the small, drenched figure standing at their side.

"Oh kiddo, what did you do this time?" Mark asks softly, directing all of his attention to her. She refuses to lift her gaze from the hallway floor and stares intently at her soaked converse sneakers.

"We found her sleeping on a park bench and she gave us this address." One of the officers explains. "Is she your kid?" He asks skeptically, taking note of Mark's age.

Mark pulls the young teenager into his arms, wrapping her trembling body in a hug.

"Yeah, I'm her brother. She goes to the park and calls me to pick her up when she has a bad day. I was asleep and I missed her calls. I'm sure she tried to wait for me or to wait out the rain and ended up falling asleep." He explained.

Amelia nods but doesn't lift her face from his chest, small arms wrapped around his back holding on for dear life. Tears of relief spilling down her cheeks and onto his skin as Mark covers for her. She is certain he will have questions, and assumes he will be angry with her too, but he didn't immediately push her away.

After a tense pause, the officers accept the story. Mark sees them out, promising to keep a better eye on his 'sister.'

As the door clicks shut, the tiny NYC studio apartment is now noticeably quiet, aside from the occasional sniffle from Amelia.

"Amy, what happened to you? What's going on?" Mark begged, trying to keep a level head as he assessed the situation.

On one hand, he knew she might have gotten herself into trouble again, possibly with drugs. Afterall, the Shepherd's were his second family and he'd had a front seat along with them as she had spiraled out of control this past year. The youngest Shepherd seemed to have a knack for making bad decisions.

At the same time, he had to keep reminding himself that she was only 14 years old. Growing up with Derek Shepherd as his best friend was the best thing to ever happen to Mark. Derek was his brother and the Shepherd family had welcomed him, and treated him as one of their own from a very young age. He learned how to be a brother from Derek, and Mark followed the example he set. Derek's unwavering devotion and protectiveness over Amelia had struck him as a non-negotiable requirement when they were young. By the time Amelia was 6 and in kindergarten, all her peers at school believed she had two big brothers.

Amelia bit her lip hard, and tried to stop more tears from spilling.

"I got into a big fight with mom. I ran off before she could kick me out for good this time." She whispered, swallowing a lump in her throat. "I got to the park and I realized I had nowhere else to go."

"I wasn't planning on falling asleep there, I swear Mark. I didn't mean to involve the police and to drag you into things. I'll be out of your hair in a few minutes and you won't have to see or hear from me again. I just, maybe could I borrow a jacket before I go?" She sniffles, chewing her inner cheek to hold back her sobs; her arms wrapped around herself protectively.

Mark felt his heart clench painfully in his chest as he realized that not only was she completely sober, but that she assumed he would want nothing to do with her. The reality of her despair turned his stomach.

"Woah, hey. Amy, stop... Where do you think you're going?" He demands desperately, seeing her head toward the door, abandoning her request for a jacket.

"Leaving, like I said. The cops are long gone and now I can go and stop dragging you into my mess. At this point, I should probably just start using again, maybe go find someplace to hide out until I die." She rattled off emotionlessly.

"At least when I'm gone I'll finally stop being the family burden; I'll finally be with someone who loves me..." She whispered, eyes threatening to spill over as she thought of her dad.

She turns and reaches for the door, ready to take a step out when a hand grabs a hold of her arm, firmly yet gently yanking her back inside.

"It's 3:30 in the morning, Amy. There is no damn way I'm letting you go off alone to god knows where and for god knows how long." He huffs with frustration and concern. He throws on a crew neck Columbia sweatshirt, toes into a pair of worn Nike's and grabs his keys. "Come on, I'm driving you home. Ma's probably worried sick about you."

Her eyes widen and she starts trembling more violently, now anxious and afraid as well as freezing cold.

"I don't have a home, I never did! I can't go back there. Please, I don't belong there!" She shouts desperately, tears flying everywhere.

But Mark isn't having it. He is out of his depth here and he knows he can't take care of her on his own. He is determined to get her somewhere safe; to someone who can help.

He shoves her, a little more forcefully than intended, into his car and runs around to the driver's side, quickly locking the doors as he hops in. She sobs brokenly and struggles to breathe as she panics at the prospect of going to her own home. He starts the car, and as he checks his mirrors and pulls out of his garage, he starts driving to the destination before he even realizes where he's headed.

He is taking her to the only place that makes his little sister feel safe. For the first time since he woke up and laid eyes on her in his hallway, Mark feels at peace. He knows he is making the right choice, even if her other big brother won't like it.

End chapter. Reviews are lovely but not needed.

Story title comes from the song Runaway Train by Soul Asylum

Chapter title while not directly named after a song I did come across Little Girl Lost by Kris Kristofferson which does fit the theme of the chapter.