The song in here is 'Ghost of a Rose' by Blackmore's Night.

The valley green was so serene,

In the middle ran a stream so blue...

A maiden fair, in despair,

Once had met her true love there and she told him...

She would say...

The Doctor sighed in contentment as he held Rose in his arms, the refrain of the music played in the background. This was one of Rose's favorite songs, and he was glad she had shared it with him. If only he could freeze time and linger in this moment forever.

Promise me, when you see

A white rose you'll think of me.

His Rose would be with him always, in one form or another.

I love you so,

Never let go,

I will be...

Your ghost of a rose...

He tightened his arms around her, reveling in the comfort of her touch. Some day he would lose her, it was unavoidable, but she would forever remain in his heart. His ghost of a Rose.

Her eyes believed in mysteries,

She would lay amongst the leaves of amber...

Her spirit wild, heart of a child,

Yet gentle still, and quiet and mild

And he loved her...

When she would say...

The Doctor walked up the high street, chasing down some errant readings, when he saw a white rose in a florist's window. His thoughts slipped back to Rose and flooded his mind with emotion. Pain. Joy. Sorrow. Love. He just stood gazing at that single flower for what felt like an age. When he moved again it was with a specific destination in mind.

Promise me, when you see

A white rose you'll think of me.

I love you so,

Never let go,

I will be...

Your ghost of a rose...

Gently he laid a boquet of white roses on the resting place of his love. Rose Tyler. With trembling fingers the Doctor traced the name on the headstone. It had been centuries since he saw her last, but every detail of her face was there every time her closed his eyes. A living memory, that laughed and smiled and cried. She smiled in his memory and he couldn't help the grin that slid across his features.

The Doctor was slumped in the captains chair in the control room of the TARDIS. His mind replaying old memories. "Play it again, Old Girl." He asked, feeling a bit like Humphrey Bogart in Casablanca. The opening strains of the song tugged at his heart as he remembered that day with Rose, so long ago.

When all was done, she turned to run,

Dancing to the setting sun as he watched her...

And evermore he thought he saw

A glimpe of her upon the moors forever...

He'd hear her say...

Promise me, when you see

A white rose you'll think of me.

I love you so,

Never let go,

I will be...

Your ghost of a rose...