A/N: @ReganGregory,thank you for this idea, you are lovely. I hope I did you, this song and this story justice. Enjoy! :)x (PS. the original lyrics have 'girl' in the first and last chorus, but since this is Jimon, I changed it to 'boy' throughout.)

---------------------------------------------------

The first time Simon noticed Jace's little habits, or quirks if you will, was when they were out with their friends. Simon had just done a gig and they stayed behind for some drinks. Maia was laughing behind the bar at some obnoxious joke Magnus had just told, while Alec was shaking his head, looking mortified. Clary was chatting with Izzy, waving her hands around and Isabelle's long, black hair, that were tied up in a ponytail, moved animatedly when she spoke. Jace was sitting on the far side of the corner, looking at nothing in particular, his face immobile and unreadable. Simon knew the blonde didn't see him staring, because he was lost in his own world.

The thing about Jace was that around other people, he could be really friendly. As in, he could wrap you around his finger with just a 'Hello'. He was just that charming, witty and well, Jace. Simon, however, knew he could be very sarcastic and obnoxious when he wanted to, Simon had gotten this attitude more times the he could count. Right now, however, Simon noticed something he hadn't noticed before. Jace was sitting at the bar, one arm leaning on the counter, his eyes empty of emotion and his lips quirked up in a smirk. But his other hand was situated on his bended knee, his finger flexing to somekind of a beat or melody. Simon knew this, because he played keyboards himself, and since Jace played the piano, he knew that it was a habitual thing to do. 

Jace's fingers moved to a certain rhythm and the more Simon watched them move, the more he could get a sense of the melody. It was the same over and over again. Thanks to Simon's musical backround, he could tell that if it would be played on a piano, it would be a sad tune. Simon knew from the moment he met Jace, that he was a closed person. He didn't let anyone too close to himself, but loved to show the facade of a charming, gorgeous, strong shadowhunter, who had the attitude of an asshole. Simon knew this was an act. And he knew this because around Simon, Jace's attitude faltered at times. Simon was the only one who called him out and gave the same attitude back to him, and took Jace by surprise every time he did this.

You tell all the boys no
Makes you feel good yeah
I know you're out of my league
But that won't scare me away oh no

Just because Jace was an asshole, didn't mean Simon hated him. He actually found it incredible endearing, when Jace showed any signs of vulnerability. It showed Simon that he was still just a human, like them. Well, as far as vampires, warlocks, werewolves and shadowhunters go, they're still part human. So it happened, that Simon saw Jace in a different way every time. And because of this he noticed little things about him. And every time it was like reading a new page of a book.

One time, in the training room, Simon had managed to piss off Jace so much, that he noticed another thing that the blonde did. When Jace was angry, his face was still controlled, but his eyes showed his flaming frustration. Burning so bright, if looks could kill, Simon would've been ashes already. But then, Simon noticed Jace was biting the inside of his cheek. It was hard to detect, but Simon was a vampire and his heightened senses helped him understand so much more now than he ever before could. And he noticed it. 

Whenever Jace was angry now, Simon would search for the little habit he had. Jace did it by fault, each time. Simon knew, that the blonde did it, because he was trying to hold back whatever harsh words he had to say. He knew how destructive he could be, and with some glee, Simon realized that Jace was trying to avoid being the person everyone thought he was. Thoughtless, reckless and sometimes, mean. Which meant that he was lying to himself and other as well. He was trying not to be someone he claimed to be. Simon wondered, what had made him this way.

You've carried on so long
You couldn't stop if you tried it
You've built your wall so high
That no one could climb it
But I'm gonna try

At some point, Simon had tried to behave differently around Jace. He tried not to snap at him, when the blonde insulted him. He tried not to look at him in anger, when they'd meet. For Simon, he discovered, it was easy to do. Because once he saw the side of Jace that he wanted to hide, it was easier to see, that Jace just wanted to be good. He just didn't know how.

There was the one time, when Simon had went to Jace's room, because Alec wasn't there and he needed someone in charge to help him with a vampire related issue, and he found the blonde sitting on his bed. He had his head bowed and he was silent. But Simon could hear the shallow breaths even from behind the door. He knew Jace wouldn't like it if he'd go in. But Simon did it anyway. When he stepped in Jace raised his head, his eyes were wet and his facial features showed Simon something he never had seen in the blonde - Jace was in pain. Something inside of him was broken. Simon felt the need to fix him. Or at least understand him.

Jace had stood up and walked to the window, his back to Simon and had tried to subtly dry his tears. "What is it?" he had snapped at Simon. The vampire's eyes softened. "Just needed to talk about a vampire issue. You okay?" he had said. Jace had scoffed and hadn't turned around. "What makes you think it's not?" Jace had said, and Simon had heard the tension in his voice. Like he was about to be discovered, so hi put his walls up so quick, Simon thought he might never get this chance again. A chance to show that someone cares. So he stepped closer to the blonde and slowly, because he knew the temper Jace had, put his hand on the shadowhunters shoulder.

Jace had stilled, but Simon hadn't moved. "Whatever it is, you're allowed to feel this way. You don't always have to be the great Jace Herondale, no emotions, perfect image of a warrior. You can sometimes be just Jace." he had said. He was sure Jace would hit him. But the blonde did something entirely different. With a shuddering breath he turned around and hugged Simon.

Would you let me see beneath your beautiful
Would you let me see beneath your perfect
Take it off now boy, take it off now boy
I wanna see inside
Would you let me see beneath your beautiful tonight

After that, they're dynamics changed. Jace was still an ass to him, and vice versa, but the words that left their mouths were not that harsh anymore, the insults never went too far, and Simon saw, that Jace thought before he said something. 

After a night out on a mission, when Simon almost got killed by a deranged werewolf, Jace had come to him, when no one else was around, and hugged him again. "Don't ever do that again" he had said to Simon. And that was that. Jace Herondale didn't want Simon to die, and Simon didn't want Jace to die, either. After that, Simon noticed another quirk Jace had. Whenever they were having a conversation, just the two of them, Jace would wring his hands. He looked like he wanted to say something, but instead busied himself with his hands, twisting them so hard, that Simon wanted to put his hands on them, ordering him to stop.

You let all the girls go
Makes you feel good, don't it?
Behind your Broadway show
I heard a voice say please don't hurt me

There was the one night, when Jace was out on a mission and Simon was in the Jade Wolf. He got a call, and when he picked it up, all that he could hear was a slow breathing, ragged but still there. And his own name, whispered through the phone. Simon knew instantly, who it was. Panicking more than he thought he would, he rushed to Catarina. She helped him track Jace, to find out where he was. Simon had first went to the Institute, to get something of his. Why didn't he tell anyone? Because Jace called him. And not Alec, or Izzy. This meant that he didn't want any of them to know, where he was. Or what was happening. And Simon knew Jace, more than he thought he ever would. So he went alone.

He found Jace at the banks of the Brooklyn river, soaking wet and almost blue from the cold, because it was early January. Rushing to his side, Simon realized instantly, what he had tried to do. Gently lifting him up, he took Jace back to his place. He warmed him up, putting him in a hot bath and staying by his side the whole time. When Jace was finally in Simon's bed, drinking tea, he had spoken. He told Simon a lot of things that night. Simon noticed, that when Jace talked, one corner of his mouth twitched, like he was amused at something, but due to the situation, couldn't laugh. He noticed this many times after that night. But the facade was breaking. After that night, Jace trusted Simon with his life.

You've carried on so long
You couldn't stop if you tried it
You've built your wall so high
That no one could climb it
But I'm gonna try

When Jace laughed, it was beautiful. It was like the wind chimes, when a breeze got caught in them and made the sweetest melodies. His face was carefree, his shoulders relaxed and his hair fell to his face in golden strands. Simon saw this many times, but the first time took his breath away. It was like seeing a clear image of the sun, too bright to watch but not so bright it burns, unless you get too close. And Jace didn't let him too close, he was very careful of that. Simon knew this, but didn't stop trying. 

Once, Jace was at his apartment, sitting on his couch and laughing at something Simon had said. He hadn't even called or sent a message, he was just at his door. And when Simon opened it, he didn't question him. If Jace wanted to be there, why couldn't he? Jace ended up passing out on his couch and Simon looked at him, sleeping, his face so peaceful, he almost wondered, was this the fierce shadowhunter he knew? The warrior that couldn't be defeated? Draping a blanket over him, Simon accidentally kissed his forehead. Jace stirred but didn't wake up. Simon, surprised by his own actions, hurried off into his own bedroom, closing the door. 

Would you let me see beneath your beautiful
Would you let me see beneath your perfect
Take it off now boy, take it off now boy
I wanna see inside
Would you let me see beneath your beautiful tonight
Oh, tonight
See beneath, see beneath
I Tonight I

On one clear and starry night, Jace was at his place again. But this time, when Simon was in his bed, his phone in his hand, the bedroom door opened a crack. When Jace came in, Simon raised an eyebrow, to which Jace averted his gaze, clearly wanting to say something. It must've been really hard for him to admit that he liked being around Simon. But the vampire didn't mind. It was almost as difficult for him. When Jace didn't move, Simon shuffled the covers around, moving a pillow to the side, nodding towards it. Jace's eyes flashed in gratitude and he slid into the bed, next to Simon, they're bodies almost touching. 

"I had a nightmare. Where I was forced to kill one of the people that I love. That I care about." Jace had said. Simon stilled at that, putting his phone away and listening intently. This was new. "Isabelle, Alec...you." the blonde continued, his voice hoarse and Simon felt the need to hug him. "I-I had to kill one, to save the others. And I couldn't do it. But I had to choose. And I-" he tried to continue, but his voice got caught up and Simon instantly knew, what he was trying to say. A single tear went down his cheek and Simon, noticing this, instinctively wiped it away, making Jace widen his eyes. The blonde turned his head to look at him, his eyes glazed over and another tear was dithering on his eyelashes. Simon sighed and pulled him in close, letting his head rest on the shadowhunters shoulder. 

"You killed me. It's okay, Jace. That's okay, it's just a dream." Simon said calmly, although his insides were screaming. Jace broke down, crying into his shoulder and Simon slid his hand on his back, rubbing it soothingly, all the while repeating that it was okay. Jace fell asleep in his arms. Simon watched him sleep, thinking about how Jace had said that he loved and cared about him. He decided that it was all that he was going to remember from his dream.

I'm gonna climb on top your ivory tower
I'll hold your hand and then we'll jump right out
We'll be falling, falling
But that's okay
Cause I'll be right here
I just wanna know

The first time Simon kissed Jace was unexpected. They were in Jace's room and the shadowhunter was waving his hands around in frustration. "Simon, I'm a shadowhunter. This is what I do." he was saying. Simon rolled his eyes, crossing his arms. "Not without back up, Jace. You always do this!" he shouted, not realizing his volume had gone up. Jace had stilled, gritting his teeth and biting his cheek. "That's just who I am." he said through the anger. Simon took a step closer and looked at him fiercely. "You and I both know that's not true." Simon said quietly. The time stood still for a moment. Jace's eyes widened when Simon grabbed his hand, pulling him closer and kissed him. Jace melted into him, like a final puzzle piece that he had missed his entire life. 

Simon felt a lot of things. Like the first snow falling, slow and steady, his mouth moved against Jace's. Like the hot summer sun, his mouth burned against the shadowhunter. Like a thunderstorm, they crashed together, sending shivers like lightning coursing through their bodies. And when Simon linked his hand in Jace's , he felt the pull, like gravity, dangerously hurdling him towards him, to the unknown. They didn't mind.

Would you let me see beneath your beautiful
Would you let me see beneath your perfect
Take it off now boy, take it off now boy
Cause I wanna see you say
Would you let me see beneath your beautiful tonight
Tonight, see beneath your beautiful

The first time Jace said he loves Simon, was the first time Simon saw another quirk Jace had. It was barely noticeable. When Jace tried to lie, he would scrunch up his nose. Like he felt bad for what he was doing. Ever so slightly, very small crinkles would form and Simon knew instantly, Jace was lying. 

"Simon, this is ridiculous. There's got to be someone else for this!" Jace was saying to him. Countless of missions later, they both still tried to protect each other, and every time both thought that they were right. It was like a never ending game. "There's only like a 50% chance I'll die." Simon joked, trying to lighten the mood in the only way he knew how - by making inappropriate jokes. This earned a growl from Jace. "Simon, so help me, if you go, I'll kill you myself, and that's a 100% chance of happening!" Jace yelled at him. "I get that you are a vampire and that you can take care of yourself, but this is far too dangerous and I wont' let the person I love, go into certain death!"

Simon stared at him in shock. "What?" he asked weakly. Jace stopped, his eyes widened as he realized what he had said. But it was too late now. Simon's teeth showed when he smiled brightly. "You...love me?" he said slowly, relishing the look on Jace's face. "No. That's not what I said." Jace immediately replied, scrunching up his nose. It was almost cute, the way he tried to deny it. Simon only shook his head, laughing when he approached Jace. "You love me." he declared. Jace rolled his eyes but shook his head again. "Don't know what you're talking about." Jace said, his eyes still reflecting his panic. Simon closed the distance between them, holding Jace's face between his hands.

"I love you, too, you idiot." Simon said, smiling at the blonde. Jace sighed in relief, but before he could say another word, Simon kissed him. Every time was different for him. Like he discovered another aspect of Jace's lips that made it all new. This time, he felt the taste of something sweet, like chocolate, and he slid his tongue over Jace's lower lip to taste him more. Jace shuddered and pulled away briefly, to look Simon in the eyes. "I love you, too." he said. Simon laughed. "I said it first, you can't say 'too'." Jace wanted to protest but rolled his eyes and smacked his shoulder. "Shut up, stupid. Kiss me again." he whispered. And Simon did just that.

Oh tonight, we ain't perfect, we ain't perfect
Would you let me see beneath your beautiful tonight

-----------------------------------------------------

A/N: Well, I don't know if this was any good, but still...vote, comment, let me know what you think! :)x