Hope is the last emotion to break; the last gift to be thrown by the wayside. And maybe it was hope that brought you back to her – maybe in the back of her mind, pushing Scrabble pieces aimlessly across the smooth surfaces of the board, she called you somehow, thinking vaguely about what your heart felt like, beating feebly under her hands, or the roughness of your close-cropped hair over her sensitive fingers. You move on, but you never forget. And that could have been it.

You know, though, that there's another reason why you're here, and it has nothing to do with the fact that she's never forgotten you. You were called somehow to take care of her; to support her through the madness that will consume her life and her friendships. It's not exactly a guardian angel's job; but she doesn't know that quite yet.

She discovers the scent of leather in her room one night after a long shift. The increasing headaches; the confusion – it's all melted away as she catches sight of you standing by the window, a trick of the curtains moving, perhaps, in the wind. She does a double-take before she realizes that it's really you.

"This isn't happening, you're not real, you're not real," she whispers to herself; she cradles her aching head with the abundance of blonde curls that spill over her ears and collar to rest on her shoulders, and you put a hand out to touch her, to prove to her that you're there and will be there through the hell to come.

"I'm real, Izzie. Touch me."

She almost refuses; she always was one for realism. But the tears trace their way down her still-full cheeks; the soft skin on her face and neck, how you loved to feel the satin against your rough, five-o'clock-shadowed cheeks even if you just shaved that morning. It's already in her eyes, but you can't tell her.

She refuses to kiss you until she touches your chest, where your heart used to beat a little more strongly against her hands, and then the surprise, delight and disbelief mix on her face and with her tears when she discovers that you're as solid as she is, standing together in a quiet room that still holds the scent of her perfume, even though the wind is cold through the window tonight.

You hold her closely, feeling her slight weight in her arms, and feel conflicted. You should feel sad; after all, a vibrant woman is about to lose herself and all that makes her Izzie. But you can't help but feel a leap of joy at the fact that you will finally be together in whatever afterlife you make for yourself; you know that was why you were sent. To make it easier. God is never that cruel.

All the same, though, it's hard to feel her in your arms without her knowing exactly why; feeling the confusion start, the forgetting of little details; the beginnings of hand weakness and loss of control; soon the insomnia and insanity taking over. She'll end her days in a palliative nursing home somewhere away from her friends and whatever family she has left, and at only 29, the prospect of seeing her, messy-haired and diapered, tangled in forgotten sheets and tied to the bed is desperately disgusting.

Izzie Stevens is dying of a brain tumour, and she doesn't know it yet. Now it's your turn to hold her heart in your hands.

And yet, you can't wait until the day you cross the curtain for good with her at your side forever.