Hi this is just a short oneshot about Sizzy. I was watching City of Bones and it just kind of popped up. This isn't in any specific time in the series.

Enjoy

"I just don't know how she'd react. I mean you didn't react very well." Simon Lewis said to his best friend Clary.

"That's different Simon, I knew you longer." Clary said turning to look at him. Simon put the video game they were playing on pause and looked at her as well.

"That's why I am worried. You knew me longer; you had a longer chance to fall in love with me." Clary shrugged. "Are you two together?" She asked.

"It's complicated. I really don't think she wants to be with me." He replied.

"Do you want to be with her?" Clary asked again. Simon was the one to shrug his shoulders this time. He really wasn't sure. He had hung out with Izzy for a while. She was beautiful, smart and she was an amazing Shadowhunter, and he was just a downworlder. He'd stay young forever and she'd grow up and marry another Shadowhunter, then have little Nephilim children with him. Simon would stay young and end up sulking over the Lightwoods who grew up without them, with Magnus Bane, the high Warlock of Brooklyn.

But honestly, he did want to be with Izzy. He couldn't tell her though. Simon was afraid of how she'd react. He didn't want her to stop talking to him forever because he slipped up and told her he loved her. He liked the moments when she would come over to his and Jordan's apartment and hang out with him. Then she'd stay the night with him, in his bed curled up with him. He'd feel the beat of her heart, occasionally missing feeling it in his own chest and he'd trace her runes and scars with his fingers.

Sometimes even, they would kiss. She'd kiss him and he would get lost in it, then she'd stop all too soon. Then she would turn around again and fall asleep. Sometimes they would kiss until they lost their breaths, and Simon would have to stop the kiss. Then on really special nights Izzy would convince Simon to drink from her. That is what would convince Simon that she really did care for him.

She was planning coming over tonight. He wanted her to know how he really felt. He was falling in love with her and he wasn't sure if she felt the same. Jace had said that Isabelle moved around to a lot of guys. That she was afraid of commitment, though she had been with Simon longer than other guys.

"I think you should just go for it. What is the worst that could happen?" Clary asked breaking through Simon's thoughts.

"A lot of things could happen!" He exclaimed.

"Oh please Simon, your being overdramatic." Simon just glared at the red head.

"She could throw up, she could walk out, and she could never speak to me again. She could say she doesn't feel the same way." Simon looked down at his shoes.

"I'm sure that won't happen." Clary looked down at her phone. "Listen I got to go. Jace needs me. Don't freak out too much." She stood up and slipped on her jacket. "I'll text you later yeah?" Simon nodded and watched as Clary left. He stood up and walked to the bathroom to take a shower.

Isabelle Lightwood stood in front of her mirror looking at the two puncture wounds on her neck. She had debated putting an iratze to make them go away, but she wanted something to show herself with Simon. It was something special they shared when he drank from her. She pulled her black blouse over her head and pulled her hair into a hair tie.

There was a knock at the door and Alec poked his head into her room.

"Hey Izzy, I was wondering if when Mom and Dad come home you could tell them I'm going to be at Magnus's for the weekend?"

"Yeah, I may not be home tonight though. If I'm not here when they get back, I'll tell Jace to do it."

"Alright, that's fine. I'll see you when I get back. Call me if there is trouble." Alec turned around to leave the room.

"Alec, wait a minute!" Izzy exclaimed to her brother. He turned around and looked at her. "Can we talk for a minute?"

"If you want to know about what I do at Magnus's apartment, I am not telling you anything." Alec said coming over to sit on the edge of his sister's bed.

"That isn't what I was going to say, but what do you guys do?" Alec gave her a look. "Alright, what I was going to ask was…how does it feel being in love?" Isabelle went to sit next to her brother.

"Well...I don't know. It just feels complete. Like, you feel better around them, and no matter where you go, you wish they were with you. You love spending time with them, and they make you laugh and make you happy. It is happiness in an indifferent form and when that person is with you, you feel special. A special only they can make you feel." Alec said.

"Is it nice…being in love?"

"I never could've dreamed it to be so amazing." He laughed a little. "I don't really know if that answers your question."

"It does Alec. Thank you." Isabelle thought about Alec's words. She had said the similar things to Simon's roommate, Jordan. He made her happy, and she was afraid that she was falling in love with him and she didn't think she could stop it. It was true that she was scared of being with someone. Her parents had problems and that scared her. But at some point in her life she needed to accept that she could fall in love and she could stick with it.

She went off to find Jace to tell him to tell their parents that Alec would be at Magnus's for the weekend. He always says the weekend and ends up staying at his apartment for over a week. She found Jace at the front doors of the Institute, welcoming Clary in. She informed Jace to talk to their parents about Alec, and then headed out to Simon's apartment like she did almost every night.

Finally she arrived to his apartment. Isabelle didn't ever feel this way. She was brave and a Shadowhunter. She fought demons and downworlders, yet she couldn't even face her fear of falling in love. She just needed to speak to Simon.

He opened the door for her and she walked in. Jordan was out with Maia, so they had the flat to themselves. They walked into his bedroom where he still had his fold out bed. She sat on the edge of it, pulled her knives out of her boots and then took her heeled boots off.

Simon came back in with a glass of water for Isabelle. He didn't like for her to drink, so he made sure there wasn't any alcohol to drink in the apartment.

"Have you had any blood lately Simon?" Izzy asked. He shook his head. "Clary said she'd ask to get me some more bags. But I'm not hungry." Izzy looked down and Simon sat down on the bed next to her.

Isabelle turned her head to study him. His hair was longer from when she first met him. His face was pale now that he was a vampire. He looked different from when he was a mundane. He didn't have the glasses he did when he came to the Institute the first time with Clary. He looked more handsome and not scrawny and dorky. He was handsome, most vampires were.

"Simon, listen we need to talk."

"Oh man, this isn't happening." Simon stood up worried. He paced in front of Isabelle.

"Simon, I have been thinking a lot. It has been plaguing my mind what's going on with the two of us. I have been so confused." Simon interrupted her.

"Listen Isabelle if you really don't want to talk to me anymore. I get it; I'm just a mundane turned vampire, who was obsessed with my best friend for a while. You have millions of better guys to be with, why would you want to be with me? I don't have anything."

"Simon…" Isabelle started but was cut off once again.

"Izzy, it's fine. I can call a cab for you to go back to the institute. I just…" Isabelle stood up and walked over to Simon. She pressed her lips against his, to stop him from talking.

"Stop." Isabelle said. Simon nodded. "Simon that isn't what I was going to say. I was about to say, I liked being around you. It's different for me. I'm happy when you are around, and I think about you when you aren't by my side. It confuses me, but there's a feeling in my stomach that makes me feels different around you. You are different from the people I have dated, and not just because you are a Daylighter vampire. And…" She paused. "I think…" She stopped.

"Izzy…" Simon started.

"I love you Simon." She blurted out. "I don't know how, but I fell in love with you, and I'm scared of what's to come, but I might as well come right out and say it."

"Isabelle…" Simon's mouth and eyes were wide open. "I love you too." He pressed his lips to hers, feeling alive even though his heart wasn't beating. He thought it was unbelievable that she had said the words he had been freaking out about all afternoon.

"Izzy, I love you." Simon said with a dorky grin. He peppered her face with kisses. She smiled up at him. "By the Angel you are such a dorky mundane." Isabelle said laughing.

"But I'm your dorky mundane." Simon said kissing her once again.