This is set only days after the final chapter of "TARDIS Child".

Disclaimer: All rights to Doctor Who belong to the BBC. Only Mara and other OC characters are mine.

POV: Mara

Date: November 2011

"Mara, what are you doing?"

I jumped when Dad's voice rasped from right behind me. In my surprise, I smacked my hand against the monitor as I spun away from the console. "Dad! I was just..." I bit my lip as he squinted at the coordinates I'd punched into the controls.

He glanced at me. "Is this about what I think it's about?"

My eyes fell to my feet. "I just left him behind without so much as a goodbye." I glanced up at him from under my eyelashes. "I owe him better than that."

Dad pulled in a deep breath and reached out to squeeze my hand. "I'll be right here if you need me."

My gaze shot up fully to him with surprise. I hadn't expected that kind of reaction. I had thought my dad's low opinion of Nathan would cause him to be angry over my desire to seek him out. I hadn't expected his support.

I gave him a timid smile as he set the TARDIS in flight. "Thanks, Dad."

He only grunted in response and waved a hand as we landed. "Go on then. And good luck. I'll be in the library if you need help." He tapped his temple. "Just gimme a shout."

The TARDIS gave me a reassuring hum when I hesitated behind her doors. I smiled up at the ceiling as I gripped the handle. "Thanks ol' girl."

I took one more deep breath, and pushed the door open.

I stepped out onto wet pavement and closed the door softly behind me. I inhaled the smells of downtown London as people hurried around me. My eyes searched over the faces and shops until I found him seated alone at a small café. I took a moment to gather my courage before I crossed the street to join him.

Nathan looked up from his papers as I stopped right behind the empty seat.

I gave him a tentative smile. "Is this open?"

He stared at me with an open mouth for a moment before he realized I had asked a question. "No! No, go ahead."

I sat down quickly and let my hands fall to my lap limply. "You must have a million questions," I said quietly after a few beats of silence.

He held up the documents he had been reading. "I've been doing research on you and your...family."

I winced at his emphasis on the word. "What is it you already know then?"

Nathan pursed his lips. "You're all time travelers aren't you?"

I smiled over his matter-of-fact approach. "Yes."

"Are you also aliens like they say?"

"Yes...is that a problem?" A small hint of worry leaked into my tone. The idea that it was possible he wouldn't be able to accept that I wasn't human only just occurring to me.

"No," he said quickly. "No, of course not."

My smile returned. "Good. I'm glad."

He smiled back, and glanced around to make sure no one was listening to us. "What happened to you, Mara? Where did you go? I know you said it was family business, and I understand why you wanted to keep secrets. I never would've believed you a few months ago. I probably would've thought you were a nutter or something...but I believe now. And I love you."

I swallowed and looked down at my hands. "Nathan, my parents—especially my Dad—have been alive for a long time. They've been all over the universe, and they've met a lot of people. And they've made enemies. Sometimes those people want revenge."

"So…what? One of their enemies came after you to get to them?"

I let out a slow breath. "It's a bit more complicated, but yeah. Something like that."

Nathan reached out and pulled one of my hands into his. "But you're alright now, yeah? It's all been sorted out…the enemy has been vanquished?" He let out a breathy laugh. I could tell he was still having a hard time wrapping his mind around all of this.

I granted him a chuckle. "Yeah; it's all sorted."

We sat in silence for a long moment. I stared down at our hands and thought over his words. More specifically, the three words I had yet to say back.

That thought set both of my hearts fluttering anxiously. Did I care for him that way?

Yes. Absolutely. That wasn't what was in question. The question now was much more complicated. How was I going to deal with these feelings? I could ask him to come travel with me. I smiled a little at the thought of showing Nathan the stars. I wanted to. Nathan and Mara, together. Hand-in-hand as we ran across the universe.

I wanted that so badly it made my hearts ache. The only thing that stopped me from asking him to come with me, and there was no doubt in my mind that he would accept, were the consequences. I'd literally grown up watching how much pain and misery this life my family led could cause. It was full of hard decisions that I knew Nathan would never understand, and I couldn't bear for him to leave because of the outcomes of those decisions. Or, worse yet, because of decisions he would be forced to make.

And even worse yet, there was always the possibility that I could lose him. Not just like how Dad had lost Mum at Canary Wharf, but really properly lose him.

I couldn't be responsible for his death.

I bit back my tears, only now realizing that it was because I loved him that there had only ever been one option.

"Mara..." Nathan reached out to touch my cheek. "Why did you come back?"

I opened my mouth to answer, and stopped when my words got stuck in my throat. "I...I came to say..." I pulled in a deep breath and braced myself. "I came to say goodbye."

He yanked his hands back as if I'd stung him. "What?"

I swallowed down the shakiness in my voice. "Why else did you think I would come back?" I nodded towards his papers. "You've done your research. You know none of us are really the types to look back at someone once we've left."

His eyes dropped. "I thought you came back because you wanted me to come with you."

I squeezed my eyes shut for a moment to hold back my tears. "Why would you think that?"

His gaze shot back up, and I flinched against the hurt I saw there. "Because I love you, and I'm fairly certain you love me, too."

I kept my face carefully neutral. "Nathan, I can't do things like that. My life...well, it's not very conducive to a healthy relationship."

"But your Mum and Dad seem to be able to work around it just fine," he countered in a sharp tone. "Why can't we?"

"Because you're young," I stated flatly. "And Human; and you're not ready for what you're asking me for."

Nathan sat back with a huff, and stared at me with an expression of disbelief. "You don't mean any of that."

"Nathan—"

"No, I see it." He sat forward and pointed at me angrily. "You say the words, but in your eyes I see it. You love me, and somewhere in there you believe that we could make it. Please, Mara, please just give us a chance. I'll stay on Earth if you really don't want me travelling with you. You could visit! I'll miss you, but it's still possible right? And you're a bloody time traveler for Christ's sake. You could come back any second you pleased!"

I let my eyes slide away to focus on his empty coffee mug. "That's not fair to you."

"How?"

"Well think, Nathan!" I gave him a hard stare. "What happens if you ever want to get married? Have children? The only reason I was born is because my mother's not Human. I can't have children with you."

"Doesn't matter to me," he muttered. "I'd have you. That would be enough."

"But I won't always have you," I countered. "My species...we live a lot longer than you. We change, but we don't die. It's called regeneration. I'm sure you've noticed that my Dad's had more than one face in his lifetime. When I'm about to die I can just regenerate, but you...you're Human. You age and you die and there isn't anything that I can do about that. So let me ask you this—how is that fair to me?"

He didn't answer.

I pulled in a deep breath and pulled a chain that held my spare TARDIS key from around my neck. "I have something for you."

Nathan only stared as I placed the key in his hands. "That key is very special. It's a key to our ship. And for the rest of your life, whenever I'm near, it'll hum. Keep it." I closed his fingers around it.

He kept his heartbroken eyes fixed on me. "Why should I?"

I leaned forward and gave him a soft kiss. "Because you're right—this one time. You're right." I stood reluctantly and turned to leave.

I felt a hand grip my wrist. "Mara." He stared up at me with a pleading expression. "Please. Don't go."

I gently pulled my wrist free and walked across the street. I felt it when both of my hearts wrenched free from my chest. I kept the tears at bay as I pulled out my spare key and opened the doors to the TARDIS. She gave me a comforting hum as I stepped inside.

Dad leaned against the console with crossed arms. He watched me with a crinkled brow and worried eyes. "Do you love him?"

I leaned my forehead against the cool wood of the doors. "What do you think?"

He sighed heavily and pulled the monitor over to him. "Nathan Daniel Robinson lived to be the ripe old age of 97. He spent most of his life in South London, teaching art at a local school until he was 75. He and a miss Sierra Redford were married at the age of 23 and had two children named Jordan and...Mara."

He paused, and I squeezed my eyes closed again. My grip tightened around the door handle.

Dad cleared his throat. "They had a very happy life together. They became grandparents shortly after Nathan retired from teaching, and only separated when Sierra died from a massive stroke at age 83."

"How do you do this?" My voice came out in a rasp, and I struggled to clear my throat.

He let out a loud breath and came to pull me against his chest. I buried my face into his shoulder. "I won't lie to you," he said, "it never gets easier. The only thing that ever changes is you get better at rationalizing things to yourself. You convince yourself you're doing the right thing."

I swallowed, and pulled away. "Where are Mum and Jenny?"

"Out," Dad murmured. "Your Mum's helping Jenny pack up your old flat."

I nodded silently.

"Do you want me to stay?" he whispered.

I fiddled with the controls of the TARDIS. "No, if you don't mind...I have something I need to do."

He nodded, and I knew that he had sensed what I was up to as he walked out. "I already set the coordinates in for you. The TARDIS will do all of the work. Be careful, love."

I felt my lips twitch into a smile. "Thanks Dad."

I waited until he was gone to start up the sequence. The TARDIS groaned as I kept her steady during the flight. She landed with a soft thud, and I gave her a pat on my way out.

The venue they'd chosen was absolutely gorgeous. It was a small pavilion that looked over tall bluffs just off the ocean. The whole place was full of lilac flowers and purple garlands, with decorations dripping from every available surface.

I slid into a seat in the back as they exchanged rings, and tried to ignore the stares and whispers as the other guests noticed me.

I couldn't keep the smile off of my face. Sierra looked absolutely beautiful in her long white gown. Her dark hair was pinned in swirls around a small veil that tumbled down her back. Her eyes were teary when she looked up at Nathan, but I could see the deeply rooted happiness in both of them.

I stood and clapped with the crowd when they kissed. I let out a small cheer when he dipped her back—a move that almost caused both of them to fall to the ground. The cheering of their friends and family grew louder when the two of them turned to face us with wide beaming smiles on both of their faces.

Nathan's expression became confused as they started back down the aisle. It was then that his eyes found mine.

I gave him a soft smile and thumbs up.

He looked like he wanted to shove through the crowd to me as he continued to lead Sierra back down the aisle. I waited until the crowd started to make its way over to the pavilion before I slipped away for the TARDIS.

"Mara!" Nathan shouted as the doors closed behind me.

I slumped back against the doors as the ship started up again. I stared up at her ceiling. "I don't know if I can do this."

She gave me a comforting flicker of her lights, which I translated into yes you can.

I sighed heavily as we landed, and stepped out.

I was present when Nathan and Sierra had Jordan, and then again when their daughter Mara was born. I fast forwarded through all of their lives. I was always there as a protector or a guardian when they or their children needed me. I knew both Jordan and Mara told their parents about me, since I never concealed myself from them. I also knew that only Nathan listened. He would catch me sometimes. Despite my best efforts, his gaze would find me at the back of crowds or as I hurried away to the TARDIS. At first he would always try to follow me, but eventually it got to the point where he seemed content with a little smile or a wave.

When Sierra died, I attended the funeral. I kept close to the wall until the church service was over. I only dared to come out of the shadows when it was only Nathan in the room.

He looked up with surprise when I sat beside him on the pew.

I took his wrinkled hand and gave it a gentle squeeze. "I'm sorry. She was my friend, too."

He gave me a watery smile. "I thought you didn't want to see me grow old."

I let out a small laugh that seemed cold even to me, and smiled when he pulled out his key. "You kept it."

He nodded. "Never took it off. It used to bug Sierra to no end."

"Then why did you keep it?"

Nathan gave me a sad smile. "You asked."

I swallowed down the thick lump in my throat before I kissed his cheek. "I have to go."

He nodded and released my hand. "I waited, you know."

I stopped, but didn't turn around.

"I waited for you in that café for hours. I kept coming back every day with the hope that you would change your mind and come back for me. That's where Sierra found me—lost in my research." He chuckled and then grew serious. "I never stopped loving you."

I half turned to face him, and gave him a small smile before I quickly exited the church.

I stopped outside of the TARDIS. I slid my hand down the door lovingly. I had one last stop to make. I braced myself, and entered the ship. She took off the moment I closed the doors, and let out a quiet chirp as she landed.

I spun around on my heel and sucked in a deep breath.

The room I entered was dark and quiet. The only sounds came from the patter of the rain outside and the soft beep of the machines monitoring his life signs.

"Now I know I must be dying," a voice rasped.

My eyes shot over to where he lay on a hospital bed. The only light in the room came from a small reading lamp turned on beside him. In his lap I could see dozens of pictures splayed out.

I gave him a soft smile and came to sit beside him. "Hey there."

He reached out with a shaky hand to touch my cheek. "You're real."

I chuckled. "I'm as real as you, Nathan."

He gave me a wide grin. "They told me you weren't real, but I knew better. They said you were just a ghost from my past."

I kissed his cheek. "I'm much more than a ghost."

He looked over to the window. "They say I don't have long now."

"Where's your family?" I whispered.

He waved a hand. "Busy."

I swallowed down the lump in my throat, and felt a warmth curl into my chest when I saw the key around his neck. "You still have it."

Nathan glanced down at the key, and smiled. "It helps me remember."

I cocked my head to the side. "How?"

A mischievous glint sparked in his eyes as he leaned in closer. "Because, this isn't just any old key. This is a very special, magical key."

I felt my smile spread back over my face as I settled further into the bed beside him. "Tell me the story."

He cleared his throat. "Long ago, there was a boy who met a beautiful girl. This girl opened his eyes to a world he never thought existed, and before he knew what had happened, he fell in love with her. They spent years together as friends, but it took a long time before the girl began to love him back. But when she did, they were both very happy—" He broke off to cough violently into his hands. "Sorry, I'm-"

I winced and reached out to rub his shoulders. "It's alright. Take your time."

He waited until his breath was back to continue the story. "Anyway, one day the girl had to leave the boy. She loved him still, but she couldn't stay. This girl was special you see, she was a time traveler. Not only that, this girl was a beautiful alien from a planet far, far away."

I closed my eyes slowly.

"Hey, I'm not quite finished yet." Nathan chuckled until I opened my eyes. "Where was I...oh yes. This girl was an alien. And she knew that eventually she was going to outlive the boy, so one day she met him at a small café to say goodbye. When she told him she was leaving without him, he begged and begged her not to go. He loved her so much and she was so beautiful. He knew that if she left him his life would become very dark and very lonely, so he begged her to stay. She loved him, he knew, even though she had never said the words. He didn't need to hear the words to know the truth."

"Nathan…" Tears welled into my eyes.

He took my hand. "But—but, he also knew that one day he would have to leave her. Whether it be because of age or sickness or aliens, he would have to leave her heartbroken and without him. The boy couldn't do that to his beloved; so when she gave him the key to her magical time machine, he took it, and he let her go."

I gave him a soft smile. "That's a sad story."

Nathan held up a finger. "You didn't let me finish. Because while the girl did leave the boy for the stars, she never did leave him completely. He saw her watching over him throughout his life. And every time she was near the key would alert him of her presence by humming against his chest. She was there, every time he needed her, and every time he was reminded of her beauty and his promise. His promise to her to keep the key forever. And his promise to himself to always love her."

I sniffed, and brought his fingers to my lips. "And did he?"

He smiled and brushed a tear away from my cheek. "Always."

I sat staring out into the rain long after they'd taken him away. The nurses had given me some funny looks, but seemed to be completely oblivious to the TARDIS. I wondered if my father had anything to do with that.

"Miss? I'm sorry, but I'm going to have to ask you to leave," a nurse with a kind face told me softly.

I nodded, and stood. "Yeah alright." I waited until she had left to unlock the TARDIS and step inside.

I let myself slowly sink to the floor as the ship took off. I hid my face in my knees when I landed, and didn't bother to look up when the door beside me opened.

"Oh Cricket," Mum murmured as she leaned down to squeeze my shoulders. "I'm so sorry."

I sniffed, and wiped my tears away, "Yeah, well..."

"Come out." She tugged me by my hands. "We have something for you."

I blinked and stood up. I let her drag me out into the house Jenny and I used to live in. Dad and Jenny were both in the kitchen with four huge tubs of ice cream on the table. Beside the pile of spoons there was also a high stack of movies.

I smiled when my eyes caught The Lion King among them. "I thought you were packing up the flat."

Dad held up a spoon to me. "It can wait."

I grinned as I took the spoon. "Isn't this a bit domestic for you, Dad?"

He chuckled. "Not if you lot are with me."

I felt the tears welling up in my eyes again, and ran forward to crush him to me.

"Shh," he murmured, and held me tightly. He kissed my temple. "We're all here for you, Little Cricket."

We spent that whole night eating ice cream and watching films. We kept each other laughing the whole time. We all needed this, I knew, and I found myself smiling happily as I watched my parents have an ice cream fight.

"This is war, Rose!" Dad cried as he flung a spoonful of ice cream at my Mum from across the kitchen.

Jenny and I laughed when it smacked against the wall nearest to us. We scurried out of the kitchen to avoid getting caught in the crossfire.

Once, I glanced out the front windows and caught sight of Nathan walking by on his way home. I felt a lump form in my throat when he hesitated. His face was full of heartbreak when he heard us laughing.

I felt a soft smile grace my lips when he kept walking.

"Live a fantastic life Nathan," I murmured. "For me."

Fin.