My name is Gwydion Harkness. The third child and second son of the beautiful, amazing and wonderful Gwen Cooper.

She used to love a man called Rhys before she began working for Torchwood, but it all changed when she met my father Jack Harkness, and fell head over heels in love for the dark haired, blue eyed, sassy American Captain.

Poor Rhys never really stood a chance.

He won her over in a heartbeat, and eleven months later he had a diamond ring on her finger.

There were slight complications when a carnivorous shape shifter bit her the day before her wedding, and made her nine months pregnant over night, but as usual, they triumphed over alien threats and tied the knot in true torchwood fashion, with the entire congregation around them sinking into retcon induced slumber.

Two half made a whole, our Mother always told us. It was the moment that made her life so much more.

It didn't take long for them to get knocked up, and nine months later there was bouncing baby, but she wasn't a normal baby.

Because when my sister Morgan was born, delivered in the Torchwood hub, her heart stopped beating for three entire minutes, before waking up and howling like a banshee in the midst of my parent's grief. A miracle they called her.

That's when they first realised my Father's immortal gene could be passed on.

A year later, my brother Tristan quickly followed, and lo and behold, he was immortal too. So far in life, he's been shot dead over six times, and ran over on several occasions. It was a good thing Mum made him carry retcon around, the shock of the traumatised drivers could have exposed my family to the world.

And so a year after Tristan, and two years after Morgan, when I came along they didn't expect any different. I would no doubt be as immortal as my two siblings and father, but no. I was the failure. The defect. The ugly ducking in the family.

And it's all down to Owen and Tosh, who decided to test me the moment I was born. Examining my DNA and comparing it with Morgan and Tristan's, they quickly realised I was mortal.

It's just as well they did, or I might not be alive today.

But that was the day I became a failure in my family's eyes, whether they knew it or not.

I almost wish they'd never done the test, because then maybe I'd have felt like I belonged, at least a little while.

Then they would only have found out on my death bed, and then that would be OK, because I'd never live to be the odd one out.

My mother Gwen Cooper, she was mortal too, had been all her life, but my Dad never left her behind, because she was all grown up, and could look after herself.

She loved me most of all, because I was all hers. Because I was mortal like her.

I wish she hadn't been. I wish she'd been immortal too, and then we'd still all be together.

She died a year ago in my very arms, because I rebelled, and snuck out to join my family against their instructions. I wanted to prove I could be useful too, and my Mother gave her life to save mine.

Before then I was kept home to keep me safe, but now it's so much more. My family claims to love me, but they resent me really; I can see it in their eyes.

They blame me for my Mother's death, and the truth is I blame me too.

And yet I know there's another reason, I can see it every time he meets my eyes. He hates me because I was the one who held her hand as she died, and that was supposed to be him, my Dad.

He knew one day she'd die and he'd live on, but he always thought it would be OK, because they'd do it together. I took that away from him.

They try and pretend they want me safe, but the truth is they despise me.

I can see it in their eyes, every time he orders me to stay home, stay safe.

And so every day, during every alien attack, every threat to humanity that turns up out of the blue, I get left behind.

Always. Always always…

I am left behind.

It's a one shot, but at a later date I might change my mind and decide to go a bit deeper.