The Doctor has been aimlessly wandering the Vortex since leaving Donna with her mother and grandfather. He can't seem to decide where to go or what to do next. Nothing appeals to him.
The TARDIS is running low on power – it took a lot out of her towing the Earth back to its correct position and then taking Rose, Jackie and Him back to the alternate universe. Time to visit the rift at Cardiff and refuel.
He moves slowly around the console, setting the co-ordinates, almost like he is in a trance. He isn't looking forward to this – not one little bit. But he has no choice – the TARDIS needs fuel and this is the closest option.
He throws a lever and the engines start to whine. The TARDIS doesn't seem to be too happy about this either. She lands roughly – knocking him off his feet.
As the Doctor picks himself up from the floor he hears a loud banging on the doors.
"Doctor," someone is calling. More banging follows.
He recognises the voice. It belongs to the last person on Earth that he wants to see right now.
"Come on Doctor, let me in. I know you're in there – I saw you land and the doors haven't opened since."
The Doctor lets out a sigh of resignation. "Better get this over with then," he mutters to himself.
He walks down the ramp, opens the door and is greeted by a grinning Mickey Smith.
"So how's it goin' Boss?" asks Mickey.
"Oh you know, same as usual," replies the Doctor. "And what about you Mickey, what are you doing with yourself these days? How long has it been since we dropped you off?"
"It's been nearly a month now. Jack convinced Martha and me to come work for him at Torchwood. They have some really amazing stuff down there. I can't wait to show Rose around the place."
Mickey is trying to peer into the TARDIS but the Doctor is blocking his view.
"Where is Rose?" comes the question the Doctor has been dreading.
The Doctor pales under Mickey's intense gaze. When he doesn't offer a reply Mickey asks again, with a forceful tone, "Doctor, where is Rose?"
"She's not here," is the whispered reply.
"What do you mean she's not here? She can't have gone to visit any of her old friends, she is dead in this reality. Did you drop her off to see Sarah Jane? I know they became quite close after we saved the Earth."
"No Mickey, she's not with Sarah Jane. She's not with me anymore. At least, not in this universe."
"Not in this universe? What are you saying, Doctor?" Mickey's stance has become threatening now.
The Doctor looks Mickey in the eye. "I left her back on the parallel world with her family."
"You. Left. Her. Where?" Mickey yells, making each word sound like a statement.
"Well I didn't actually leave her – she left me. She chose to stay there."
"Oh no you don't, Mister. Something's not right about that. Why would Rose leave you when she spent all that time trying to get back to you? What did you do?"
The Doctor took a step backwards, trying to put some distance between himself and a clearly angry Mickey.
"I didn't do anything. She chose to stay with Him. I had to leave him there, he's too dangerous to let him stay in this universe."
"I don't believe you – there has to be more to it than that!"
"He's part human. He can give her what I can't."
"And what's that?" asks Mickey.
"He can give her forever – her forever, not mine."
Mickey gives the Doctor an odd look. "Come on Doctor, this is Rose you are talking about. She is not some fickle female. Something else must have happened."
The Doctor hangs his head. "He told her that he loved her. That's why she chose him."
His voice is getting shaky and his eyes are welling up with unshed tears. He shakes his head, clears his throat and looks up again.
"It's for the best anyway. She can keep an eye on him – stop him getting into trouble."
Mickey still doesn't look convinced. "But why would he tell her that?"
So the Doctor explains the events as they had unfolded at Bad Wolf Bay, ending with him and Donna leaving while Rose was kissing Him.
Mickey has listened quietly to the Doctor's story but now he bursts out laughing. He is laughing so hard that he has to hold his sides, they are aching so much.
The Doctor is starting to get annoyed now. "What's so funny?" he asks impatiently.
"You are. And you call me an idiot. Well who's the idiot now then, Doctor?" He doubles over, roaring with laughter again.
"I've had enough of this. Just stop it and tell me what you mean," the Doctor demands.
Mickey sobers up immediately. He knows that tone of voice – the Oncoming Storm is brewing. It is better not to mess with him when he is in this mood.
"You really don't have any idea about women do you Doctor? Rose was trying to make you jealous, show you what you were missing out on! There is no way in a million years that she would choose to stay with him over you. It is you she loves. You and the TARDIS and travelling in space and time. And now you have taken all that away from her, without even asking her if it was what she wanted."
The Doctor is silent, slowly processing what Mickey has just said.
Mickey watches the emotions play over the Doctor's face. First there is disbelief, which slowly changes to hope then dawning understanding and finally despair.
"Oh my poor Rose. What have I done to her, Mickey? What have I done?"
With that the Doctor sinks to the ground, his back against the door of the TARDIS. He puts his head in his hands and finally allows his true emotions free reign, no longer caring who sees them. He sobs as if his hearts are breaking, lamenting what he has done to himself and his lost Rose.