(Can we just take a moment to appreciate David Tennant and all his adorable glory in that picture? lol)

I bite my lip, watching the Doctor as he rushes around the console. Rose was hiding halfway behind a coral pillar, holding onto it. Hermione was staring at the Doctor in shock; she knew about regeneration, but she'd never seen it before now.

"6 PM... Tuesday... October... 5006... On the way to Barcelona!" the Doctor turns to me, grinning and extremely pleased with himself, oblivious to the two humans. "Now then... what do I look like?" he asks and I open my mouth to answer, but he holds up a hand before I can. "No, no no, no no no no no no no. No. Don't tell me," he points at me and I shake my head, amused. "Let's see... two legs, two arms, two hands..." he moves his wrist, testing it. "Slight weakness in the dorsal tubercle," he frowns before his hands fly up to his hair. "Hair! I'm not bald!" he laughs, making me giggle as he runs his hands through his hair excitedly. "Oh, Oh! Big hair! Eva, come feel it!" he beams at me. 

I roll my eyes with a smile as I step up to him. The Doctor smiles giddily as he leans down to my level and I run my hands through his amazingly soft new hair. 

The Doctor suddenly feels the sides of his face: "sideburns, I've got sideburns!" he cheers. "Or really bad skin," he grimaces. 

"They're sideburns, your skin's fine, sweetie," I snort. 

The Doctor smiles and straightens back up, slapping his stomach: "little bit thinner... that's weird. Give me time, I'll get used to it," he shrugs. "I... have got... a mole, I can feel it," he says, looking as though he's discovered the cure to some rare disease. "Between my shoulder blades, there's a mole," he rotates his shoulders. "That's alright, love the mole," he grins happily. "Want to see it?" 

"No, keep your clothes on, bozo," I snort. 

"Go on then, tell me," he straightens and holds his hands out. "What do you think?"

I go to answer, but once again I'm cut off: "who are you?" Rose asks, her voice quiet and scared. 

The Doctor and I both turn to her, his face falling and mine turning a little sheepish. I had basically forgotten they were here. 

"I'm the Doctor," he frowns at her. 

"He's the Doctor," I nod, pointing at him.

"No..." Rose shakes her head. "Where is he? Where's the Doctor? What have you done to him?" she asks, her voice rising.

"You saw me, I... I changed..." the Doctor points over his shoulder. "...right in front of you," he mutters. 

"Rose, it's... it's really him," Hermione says, coming out of her shocked state. 

"Bookworm!" the Doctor cheers, rushing over to her. "Come here, you!" he pulls her into a tight hug, making her squeak in surprise.

"You're not him," Rose shakes her head as he pulls away from Hermione. "I saw him sort of explode, and then you replaced him, like a... a teleport or a transmat or a body swap or something," she takes a few steps toward him and pushes his chest. 

The Doctor rocks back on his feet, hurt and completely lost for words. I stare at Rose... I knew she'd have a hard time understanding, but she literally saw him change with her own eyes. 

"You're not fooling me," Rose glares at the Doctor. "I've seen all sorts of things. Nano genes... Gelth... Slitheen..." she gives him a dark look and he just raises his eyebrows. "Oh, my God, are you a Slitheen? Eva, get away from him!" she grabs my hand and pulls me behind her. 

"I'm not a Slitheen," the Doctor says calmly while Hermione and I share a confused look. 

"Send him back," Rose glares at him. "I'm warning you; send the Doctor back right now!"

"Rose, it's me, honestly, it's me," the Doctor pleas, leaning toward her. 

"Stay away!" Rose yells, stepping back and taking me with her. "How can you trust it's him?" she turns to me. 

I glance at the Doctor, who looks hurt and confused as to why his friend doesn't believe it's really him. 

"Doll," I put my hands on her shoulders. "The Doctor... he was dying and to save himself he had to change... every single cell in his body, but it's still him," I try to assure her. 

"He can't be," she whispers. 

The Doctor takes a step over to us and I turn Rose to him: "then how could I remember this?" he raises an eyebrow. "Very first word I ever said to you. Trapped in that cellar. Surrounded by shop window dummies.... oh... such a long time ago, I took your hand..." he grabs her hand. "I said one word... just one word, I said... 'Run'," he whispers. 

"Doctor..." Rose stares up at him. 

"Hello," the Doctor grins down at her.

Rose sighs in exasperation and stumbles back. The Doctor beams and starts to rush around the console: "and we never stopped, did we? All across the universe; you, Eva, and me! Running, running, running... one time we had to hop," he laughs. "Do you remember? Hopping for our lives," he starts to hop up and down on one foot, making Hermione and I snicker. "Yeah? All that hopping? Remember hopping for your life? Yeah!? Hop? With the..." he calms down a bit. "No?" he asks and I turn back to Rose. 

I frown as she was staring at the Doctor, still cautious of him. Oh, for the love of- why can't she seen it's him!? 

"Can you change back?" Rose blurts out, making my eyes widen.

"Do you want me to?" the Doctor asks quietly. 

"Yeah," she nods and I gape at her.

"Oh," the Doctor murmurs. 

"Can you?" she asks.

"No," the Doctor shakes his head.

"Rose, stop it!" I glare at her and she turns to me, shocked. "Can't you see how much you're hurting him? You're supposed to be his friend, his sister even, if what you shouted at your mum is anything to go by!" I glare at her and the Doctor looks at her in surprise. 

"But how can you just accept him as the Doctor?" she asks me quietly. "I thought you loved him," she frowns. 

"Just because he looks and sounds like a different man, doesn't mean his is," I groan, choosing to ignore the part about me loving him. "He's still got all the same memories and it's still him at his core," I tell her and she just stares at me. 

"Rose..." Hermione says cautiously and she turns to her sharply. "Eva, she's been through this herself and she's still the same person I went to school with... she's got different quirks and looks, but she's still Eva," she tries to help.

"You've... you change like him?" Rose turns to me and I nod, watching her reaction. "Are you going to?" she asks, tears in her eyes. 

"Not if I can help it," I snort, shaking my head. 

"But it's not... he's not..." she splutters, looking between the three of us. 

"Do you want to leave?" the Doctor speaks up and I turn to him sharply.

"Do you want me to leave?" Rose asks, shocked. 

"No!" he assures her quickly. "But... your choice... if you want to go home... cancel Barcelona," he goes over to the console. "Change to... London... the Powell Estate... ah... let's say the 24th of December," he looks over at Rose. "Consider it a Christmas present," he smiles. "There," he steps back and tucks his hands under his arms defensively. 

"I'm going home?" Rose asks.

"Your choice," I shrug, leaning against the console and folding my arms. "Back to your mum, it's all waiting for ya..."

"Fish and chips, sausage and mash, beans on toast... no, Christmas! Turkey!" the Doctor cheers happily. "Although... having met your mother... nut loaf would be more appropriate," he grimaces, making Hermione and I laugh. 

I beam when I see Rose smile, but she quickly looks down to hide it.

"Was that a smile?" the Doctor asks her, smiling as well.

"No," Rose shakes her head. 

"That was a smile, doll," I tease.

"No it wasn't," she mutters. 

"You smiled..." Hermione nudges her, grinning. 

"No I didn't," she stays firm. 

"Oh, come on, all I did was change, I didn't-" the Doctor suddenly gags and the TARDIS shudders, making my eyes widen. 

"What?" Rose frowns. 

"I said I didn't-" he gags more violently and I rush over, cupping his face. "Uh oh," he frowns down at me. 

"Don't touch the console," I warn him, stroking his cheek with my thumb. 

"Um... are you alright?" Rose asks, edging over to us. 

I watch as some regeneration energy floats from the Doctor's mouth and wrinkle my nose when it curls around my neck before disappearing. 

"Doctor...?" Hermione frowns at him worriedly. 

"What was that?" Rose asks. 

"Oh... the change is going a bit wrong and all-" the Doctor gags again and stumbles. 

I squeak as I'm pushed into the console with the Doctor leaning heavily against me: "I know, sweetie, I know," I coo and push his hair back as he moans in pain. 

"Look... maybe we should go back," Rose suggests. "Let's go and find Captain Jack, he'd know what to do." 

"Gah, he's busy!" the Doctor pushes himself up suddenly and I watch him warily as he walks around. "He's got plenty to do rebuilding the Earth!"

"Doctor, maybe I should help you get some rest..." I tell him cautiously. 

"Oh, come on, love! Where's you're sense of adventure!?" he turns to me with a crazed gleam in his eyes before looking down and my eyes widen. "I haven't used this one in years!"

"No!" I rush forward, but I'm too late to stop him and he throws the lever down. 

The TARDIS shudders violently and Rose and Hermione scream as they hold onto the console. 

"What're you doing!?" Hermione demands. 

"Putting on a bit of speed! That's it!" the Doctor shouts crazily and I follow him around the console, undoing any more damage he could do. "My beautiful ship! Come on, faster! That's a girl! Faster! Wanna to break the time limit!?" he asks me excitedly. 

"Stop it!" Rose screams, terrified. 

"Doctor, you need to rest!" I glare at him.

"Ah, don't be so dull... let's have a bit of fun!" he scoffs nastily. "Let's rip through that vortex!" he shouts before calming for a moment and looking at me. "The regeneration's going wrong, I can't stop myself," he leans into me as he grimaces. "Ah, my head..." he groans out before springing back upright, his voice going crazed again. "Faster! Let's open those engines!" 

"Don't touch anything!" I slap his hand away from the controls as the cloister bell rings. 

"Eva!" he pouts dramatically and I roll my eyes at him. 

"What's that?" Rose asks. 

"Something very not good!" Hermione shakes her head, tightening her hold on the console.

"We're gonna crash land!" the Doctor laughs manically. 

"Merlin, you're even madder when you regenerate," I sigh, rubbing my temples. 

"Well then, do something!" Rose shrieks at us. 

"I can't do anything," I shake my head, holding onto the console. 

"Too late! Out of control!" the Doctor agrees, giggling insanely. "Oh, I love it! Hot dawg!" he hops in place excitedly.

"You're gonna kill us!" Rose and Hermione scream.

"Hold on tight, here we go! Christmas Eve!" the Doctor cheers.