Sets kind of after City of Lost Souls, but years and years after the last fight against Sebastian and the Dark Shadowhunters.

This is a Songfic. Don't like, don't read.
Song: "Waiting for you" by Richard Marx

Also this is a Oneshot, there won't be a sequel. I was just very much in the mood for something short & very very sad (you have been warned) then I heard that song.
I do hope you like it! (I also recommend you listen to the song while you read it. I have listened to it over and over again, while writing.)

WAITING FOR YOU

Ocean's apart day after day

And I slowly go insane

I hear your voice on the line

But it doesn't stop the pain

When Simon became a Vampire he hadn't thought of the consequences – of course he hadn't, he had been too busy dealing with the fact that from now on he was technically dead and had the urge to drink blood. It had been horrible – and yet he would happily relive his death and awakening as a Vampire over and over again, if that would turn back time. He was willing to go through every horrible task heaven and hell had to offer to turn back time long enough, for him to save her. But no one cared. No one was offering him a way to save her.

Since the last time he saw her he couldn't think of anything but one question: Was she still alive? If so, where was she? Why hadn't she come to see him? Was she happy? Okay. Maybe it was more than just one question. He wouldn't even care that she wasn't with him, if he only knew she was still out there... alive. Or as much alive as she could be, considering what happend. The fight against Sebastian and his army of Dark Shadowhunters had been hard and painful. There had been countless deaths and even though it's been 50 years Simon had no idea whether Isabelle had been one of them or not.

If I see you next to never

How can we say forever

Clary was still alive. Jace was still alive. And Alec was still alive. From his friends, that was it. Of course they were now almost 70 years old, which made it very weird to hang out with them. He was pretty sure that strangers thought Clary and Jace where his grandparents, because they were the ones wearing wedding rings. He often pretended to be fine around them. They'd had to deal with their friends – and family – dying as well and Simon didn't want to go around reminding them that he had lost the girl he loved. He girl he would always love.

And the girl who actually managed to be dead and alive at the same time. He often thought of this situation like it was Schrödinger's cat. The scientist had once done an experiment in which he had put a cat in a box, together with a flask of poison which was to be released – but no one knew exactly when. Which meant until the box was opened the cat could be looked at as both alive and dead. It was the same deal with Isabelle. Except that he hadn't had an opportunity to open the box yet... because in this case the box – was the entire world. And her poison – had been Vampire blood.

Wherever you go

Whatever you do

I will be right here waiting for you

Whatever it takes

Or how my heart breaks

I will be right here waiting for you

Simon remembered everything as if if had been yesterday. After Sebastian had killed Magnus, Alec had gotten furious. His rage had made him even stronger than he and he probably would have killed him - if he hadn't gotten to Isabelle first. He had ran a sword right through her chest. Simon still remembered the way she had looked like – her eyes wide open, more in shock than in pain, and then she had sunk to the ground. Simon had been with her at that very second, holding her in is arms.

"And... I was worried about getting old and wizened one day. And what you would think of me." she had said.

"You'll find out. You'll survive. And... not to spoiler you or anything, but I'll still love you. Because no matter what you look like you're still Isabelle."

Her breath and voice had become shaky. "Simon... I... want to st" she had coughed blood. "I want to stay here. I want to see that bastard die..."

"Here? What do you-" and then he'd understood. "Izzy, are you sure? You're a Shadowhunter. If you became-"

She'd cut him short. "I would be with you."

He'd swallowed hard but had also known that he hadn't had much time. So he'd done it. He'd bit his own wrist and had given her his blood to drink. But before he could have known if she'd swallowed it, a demonic blast had hit them out of no where. They had been separated and the blast had thrown Isabelle through a portal – of which no one had any idea where it had lead. Simon had been on his feet right away but when he'd reached the portal it was closed. And Izzy had been gone.

I took for granted, all the times

That I thought would last somehow

I hear the laughter, I taste the tears

But I can't get near you now

The life of a Shadowhunter was usually short and painful, Simon knew that, even back then. And yet he'd never thought that he'd lose her this soon. Even though the possibly that she was still alive was very... very low, he needed to believe it. And he didn't, even if he neither knew if she'd managed to drink any of his blood nor if the last time he had drunken her's had been close enough for the transition to work. But even assuming that all of that had worked out – maybe she didn't make it. After all the transition into a Vampire wasn't always successful. However, not knowing what happened to her made things even worse.

He stood at the memorial, where every name of every person, who had died in the battle had been written down, staring at one specific name: Isabelle Sophia Lightwood. Everyone assumed she was dead. Even Alec had had to make his piece with that, because he had been in danger of going insane. Jace had killed Sebastian in the end but it hadn't changed what happened: Alec had lost Magnus, whom he had just started dating again. Unable to accept that his sister was gone as well, he had searched for her for years... Simon had helped. Everyone had. But it had come to a certain point where the search became pointless and eventually they had been forced to give up.

Wherever you go

Whatever you do

I will be right here waiting for you

Except that Simon never did. The moment he accepted that she was dead... even if it was the most likely possibly... he would truly die himself. He was a Vampire but he had preserved a lot of his humanity and he wasn't prepared to let that go. That part was what Isabelle had loved about him. She'd accepted that being a Vampire was a part of him but she'd loved him for him. Letting that part go felt like disappointing her. And he could never disappoint her.

He put down a rose of the bottom of the memorial, knowing it was almost impossible for her to still be alive. And yet, he couldn't help it. For as long as he would live – which, for a vampire, was a very long time – he'd not only love and miss her. He'd also wait for her. As long as it took for her to find her way back to him. No matter how miserable his life was – the very though that there was even the slightest chance that she was still out there made it worth living.

"I'm here, Izzy." he muttered. "I'll always be here."

Whatever it takes

Or how my heart breaks

I will be right here waiting for you

Told you it was sad. Please don't forget to leave a review it would mean so much to me!