Being Human, Series 3

Herrick:
You know the Old Ones, they kill at will. But they don't recruit lightly. In fact, most of them only do it once. They choose a protège. It's an eternal bond.

Mitchell:
I don't need a protège.

Herrick:
It isn't always about you. Why do you think some of us live forever and others are like... fireflies?

Mitchell:
Because some of us are smart and some of us are stupid.

Herrick:
If you choose an heir, they inherit all your secrets. They become a dark angel. Your protector. Your savior.

Mitchell:
Savior from what?

Herrick:
Oh. Perhaps a fate we've been led to belief there is no salvation from.

Mitchell:
So... if something happens to you...

Herrick:
They can bring you back.

Mitchell:
And that's possible?

Herrick:
That and so much more.

Mitchell:
So you want me to be your heir?