Ten/Rose AU from the prompt "AU having to sit beside each other on a packed train while going somewhere"

Hope y'all enjoy! As always, all mistakes are mine.

Rose boarded the train at the last minute, weekend bag in hand and face flushed from running through the station. She glanced around the full cabin in search of an empty seat.

There. She made her way to the back of the car and plopped down in the seat, not sparing a glance at the person she'd be sitting next to on the five hour journey up to Edinburgh.

She fished her book out of her bag and was settling in for the duration when a movement to her left caught her eye and she glanced sideways to assess her travel companion. As soon as she made eye contact, she promptly dropped her book.

"What the hell are you doing here?" she hissed, narrowing her eyes at the man in a pinstriped suit who was lounging in the seat next to her, smug smile doing nothing to hide the panic in his eyes.

"Same as you, I'd assume, going to Scotland," he replied dryly.

"You are walking a fine line James McCrimmon," she warned.

"Why? Because I stated the obvious? Told you I was going travelling, didn't I?"

"You walked out on me two years ago and left me a bloody note with a shit explanation and no way to contact you. Give me one reason I shouldn't see if I can match the slap my mother gave you."

Rose was letting the anger control her even though she knew she shouldn't. It was just so much easier to be angry than to remember the heartbreak of coming home to an empty flat and a note that explained nothing of why her lover had decided to do a runner.

He winced. "Because we're on a full train and are stuck together for the next five hours?"

"I've waited two years. I can wait another five hours to deliver that slap."

"Rose…"

Her eyes shut involuntarily, savoring the way he said her name. It had been so long and no one else had ever made it sound as precious as he managed. But she had to remember it was all a lie.

"The puppy dog eyes aren't gonna work this time, James. I want an explanation. I need to know why you just up and ran and left me."

James met her gaze and she saw all the shields that he normally hid behind drop. The pain and grief and love that shone in those brown eyes caused her heart to stutter.

"You're not going to like it…" he warned.

"Anything's better than the nothing I've been living with until now. You have five hours…better get started."

James swallowed hard. He knew that look on Rose's face, that hard mask of determination that warned she was not going to budge. He could see the anger and the hurt swirling underneath it too but nothing was going to deter her from demanding to hear his explanation.

God, he wanted nothing more than to slip his hand in hers and just let her presence soothe him. It had been a long two years and he'd never stopped missing her, never stopped feeling that ache in his heart whenever something reminded him of the precious girl he'd left behind.

(Those reminders happened multiple times a day. It was seeing a couple holding hands or someone drenching their chips in vinegar. It was Star Trek references and cuppas that were never as good as the ones she made. It was the dreams of her almost every night, of being with her and losing her a thousand, a million different ways.)

James desperately wanted to see her smile just one time before he started his explanation. Just one smile to treasure for the rest of his life, because he was certain that once she knew everything, she wouldn't be able to get away from him fast enough.

"James?" Rose sounded worried, despite how angry she was.

That was his Rose, caring to the last. He must have looked as desperate and panicked as he felt. She always laid him open like this, made the emotions that it was so easy to suppress around everyone else bubble straight to the surface. She held so much power over him but never seemed to realize it, never even attempted to exploit it.

"Right, yes, sorry. Explanation," he babbled, trying to get a hold of himself. He owed her this and so, so much more.

"The thing is, Rose, before I met you I was not a good person. I wasn't even making an attempt to be a good person, couldn't find a reason to try, not when I was paid so well to ignore any tiny protest my conscience might make."

He glanced at her, meeting her eyes briefly to gauge her reaction and then letting his gaze skitter away again to focus on the chair-back in front of him.

"I did so many horrible things, things I don't ever want to admit to. There's so much blood on my hands, Rose, and for the longest time it hardly bothered me. But then I met you.

"It was like a light came on. That's the only way I can explain it. You made me want to be better, to want to try to be a good person. The more I got to know you, the more I tried to wash the blood from my hands because I didn't want the stain to touch you. You're just so effortlessly good, Rose, and I knew I didn't come close to deserving you but I wanted you so badly."

"A past doesn't define who you are, James," Rose interrupted quietly.

"When it's as dark as mine it does. The fact of the matter was you were so good for me and I was bad for you. The eighteen months we had together were the best days of my life. You healed me without even knowing how or why I was so broken"

"Why didn't you say anything?" So many of John's actions while they were together were starting to make more sense now that she had the merest hint of his background.

"Because I'm selfish. I didn't want the love in your eyes to go out, couldn't bear to see it turn to hate and disgust. So I just kept lying because I couldn't lose you." James' face was open, brown eyes pleading with Rose to believe him.

"If you didn't want to lose me, then why'd you leave? There was no warning or anythin'." She could feel tears gathering in her eyes and tried to will them back. "You tore my whole world apart, James. You left me with nothing but a useless note and broken heart and I still don't know why."

Her voice cracked on the last word and James could feel his heart throb with the same pain.

"I left because I had to protect you. I thought I'd covered my tracks, that my past wouldn't catch up with me, but someone found me. I couldn't risk them trying to use you to get to me so I took off." He reached out and took one of her hands in his. "I was trying to keep you from getting hurt."

"You should've just told me. You hurt me worse than anyone else could have." She sniffled, but she didn't pull her hand away. "God, you could've told me, James. I was so in love with you. I would have understood, or at least tried to. But you just left and you broke my heart and I get that you were trying to do what you thought was best but you can't just make decisions for someone else like that!"

It felt like a red-hot knife plunged into his heart at her use of the past tense when talking about loving him. When they were together, she'd told him she loved him multiple times, always making sure he knew and understanding that he felt the same way even when he couldn't get the words out.

The night before he found out that he was going to have to run again, he'd finally whispered them to her right before she fell asleep, wrapped in his arms. It was one of the memories that had helped him get through these past two years.

He'd known all this time that it was unlikely that she still loved him after what he'd done but it had not kept him from hoping. Everything that James had done since he walked out of the life he and Rose had been building together was with the express purpose of making sure she would always be safe.

He'd hoped that once he finished this one last mission in Scotland, he would be able to go back home, to beg for her forgiveness and possibly start again. It was a long shot for sure, but he wasn't willing to give up on her, on what they had together.

But now, now he knew before he even finished his mission that there was no going home for him. She was his home and he'd torn it down when he left and was no longer welcome now that she had rebuilt.

"I'm sorry," James finally said, looking away once more. He felt so raw and vulnerable. How was he going to survive the rest of this train ride next to her without breaking down?

"I know, you're always sorry." There was a hint of bitterness in her voice and she extracted her hand from where it lay in his. Memories of all the times he'd said sorry and then just withdrawn in on himself, shutting her out, rose to the surface of her mind. "Always sorry and never doing a damn thing about it. Should've known two years wouldn't have changed a thing. Were you ever going to come back and tell me why you disappeared? I haven't heard a peep from you since you walked out. You say you did all of it to protect me, but did you think about me at all?"

"Of course I did! Every day Rose. Every day. The only reason I made it through was because I was doing it for you and as soon as I was done with making it safe and erasing any trace of me from the shadowy world I used to live in, I was going to come back and explain and beg you to understand. I wasn't - I couldn't just forget you, Rose Tyler. Ever. This trip to Scotland is my last mission and then I was coming back, knowing you probably didn't want to see me."

"That's the thing, James. I want so badly to be able to say that I never wanted to see you again. That I never want to see your face once I get off this train and walk the opposite direction from you on the platform. You hurt me, really hurt me and I tried, oh how I tried, to hate you. But I can't. I can't say any of that and actually mean it."

James' head shot up, looking at her hopefully.

"And God, you give me those puppy dog eyes like you're trying to convince me to buy the biscuits that you like and I just want to tell you that it will all be okay but I don't know if it will." Rose couldn't stop the tears from spilling out of her eyes. "I never stopped loving you, James. I tried, but I couldn't do it. I'm still so angry about you leaving and not letting me have a say in any of this but it's because I care so much. I don't know where all of this leaves us but I...I don't want to lose you again."

A grin spread over his face, making him look years younger. "I don't want to lose you either and I don't know where it leaves us but I know I want to try again to build a life with you. If you want, of course."

"If we do this, there can't be any more secrets that affect me, James. I'm not going to make you divulge everything that you've done but you can't just hide who are and make decisions for me."

"I can't promise I'll be any good at not keeping secrets since it's what I've done my whole life but, for you, I'll try. I love you, Rose Tyler, and I will do anything you want for the smallest chance to try again."

"You daft man, of course I'm going to give you a chance. I want to build a life with you. I want you, past and danger and everything."

Both their eyes were shining with tears when James reached over and took her hand once more, entwining their fingers. It was an unexpected new start for them and neither of them would trade it for the world.