My first Mortal Instruments fanfiction and I think this may be a chapter fic, but I'm not sure. I have some ideas for a few more chapters but we'll have to see where it goes. The story doesn't seem quite finished as a one-shot. Also, I haven't read City of Fallen Angels yet, but I will soon (if I can find somewhere that sells it around here), so anything that doesn't seem to quite jive with the story line of the books is probably because of that (unless it's because I got my timeline off...again) Anyway I hope you guys enjoy!

Disclaimer: I own nothing, probably not even the idea.

Clary was scared. She'd faced down demons and hordes of the Forsaken. She'd faced hostile vampires and werewolves and even her own father who was hell-bent on her destruction, but nothing could make her as terrified as what she was facing at this exact moment. Not even a Fearless rune could wipe away the terror that gripped her heart. She wouldn't tell anyone why she was more jumpy than usual. She knew what they'd tell her.

"Just go take a test and make sure."

"Vampires can't father children."

Or the inevitable.

"What about Jace?"

That was the worst part yet. Clary might be pregnant…but the man she loved wasn't the father.

The father was her ex-boyfriend yet still best friend, Simon. It was a long story and she regretted every minute of it, but there was nothing she could do to change it now.

After the incident on Valentine's ship, she and Simon had gone back to Luke's to spend some time together. They lay together on her bed, staring at the ceiling like they had since they were children, when suddenly Simon leaned over her.

"Clary…."he began.

"Hmmm?"

He stared into her eyes and whispered, "I love you." Before she knew what was happening, Simon had kissed her. Hard. Clary didn't know what had come over her, but she kissed him back feverishly. Maybe it had something to do with almost losing someone that she'd spent the greater portion of every day with for as long as she could remember.

As he kissed her and touched her, part of her could almost believe that it was Jace kissing her so tenderly. Her imagination even replaced Simon's unsure touch with Jace's strong, reassuring one. She remembered thinking bitterly that if she couldn't have him for real, then this would probably be the closest she'd ever get.

She woke the next morning nauseous. What had she done? What had she allowed to happen? Simon had left in the night, claiming he needed to get home before daylight, but they both knew he wasn't bound by the sun anymore. He was as unsure as she was. No, she wasn't unsure. She KNEW it was a mistake and that they couldn't allow it to happen again. It would NEVER happen again. After that day she'd practically cut all ties to the young man who was once her closest friend. It hurt, in a way, but she knew that he would want more when there was no more for her to give. Her heart didn't belong to him, but how did she tell him that without crushing him?

Not long after that they'd broken up. And then she'd learned the best news of her life. She wasn't related to Jace.

So life went on like a fairy tale for the next month or so. She and Jace could finally be together and they took advantage of that fact, spending almost every waking moment kissing, holding hands, or simply sitting together in the booth at Taki's. Then, suddenly, Clary began to throw up. She couldn't fathom why she was suddenly so sick, but had decided to blame it on Isabelle's cooking the night before. After almost four days of the same, however, she finally admitted what she'd been dreading all along. She was having a baby. But as if that wasn't scary enough, she and Jace had never gone beyond making out. The most terrifying part of it all wasn't that she was having a baby, it was that she was having Simon's baby.

For the past several days, Jace and Alec had been in Idris with Alec's parents doing some top secret work with the Clave. Clary didn't even know when she would see him again, and part of her dreaded having to tell him her secret. Of course he knew that she and Simon had slept together and, after several days of pouting that he wouldn't get to be her first ("Who said you would have in the first place?" she'd told him), Jace had finally forgiven her…but what would he say now that he knew that there were going to be consequences?

Clary's phone began to vibrate on the table beside her bed and she read the text message from Isabelle.

"Get over here now! The boys are home!"

Before she could even drop her phone, she vomited again, this time out of fear. What was she going to say to him? She hadn't been planning on having to tell him for weeks!

After she was relatively sure she was finished vomiting, she dressed and ran the brush through her hair, taking longer than she would have only a few short days ago. Before she would have run there in her pajamas to see him as quickly as she could. Now, though, she wasn't sure she could look him in the eye.

She walked into the old library and couldn't believe her eyes. There he was, unharmed save for a few more scars here and there. Her heartbeat quickened and her vision narrowed until he was all that she could see. When she'd opened the door fully, he turned, eyes widening.

"Clary." He breathed.

That was all it took. She launched herself into his arms and sobbed. She cried for all the time they'd spent apart, thinking they were brother and sister. She cried for the fear she had that he might have been hurt or killed while fighting in Idris. And she cried even harder for the secret she bore, possibly literally, within her.

Through her tears, Jace simply held her as tightly as he could without hurting her. He whispered her name as if it was a mantra and to stop saying it would be to stop breathing. How he'd missed her while he was away. He'd wished so many times that he could go back home…back to her. He'd almost given up on his quest and simply left more times than he cared to admit. But when her cries failed to subside after several minutes, he knew something was wrong. He signaled his family that he needed to be alone, and they graciously left the room. It was only then that he pulled away from her far enough that he could look into her eyes.

"Clary…what's wrong? I've never seen you like this."

The tears kept falling, "Jace….I…I love you."

He smiled, "And I love you, but there's something else isn't there?"

She didn't want to, but she knew she had to tell him. So, reluctantly, she confessed everything to him. When she finally admitted her secret, Jace froze.

"You…what?"

Clary locked her gaze on the ground, ashamed. "I…might be pregnant." She whispered. "And if I am…Simon's the father."

There was a tense silence for the next several moments as Jace's mind processed what had happened.

"Are you sure you're pregnant?" he asked her.

"If you mean have I taken a test, then no, but I haven't been able to stop throwing up for almost a week now…

Before she could finish what she was saying, he backed away.

"Clary…I…I've got to go. I need to think." Jace Lightwood never stuttered, she realized, but this time it was all he could do to get the words out of his mouth before he ran out the door.

Clary fell to her knees on the carpeted floor of the library and once again began to cry. The only man she'd ever loved, the man that she'd give her life for a thousand times over, had just walked out of her life forever.

~ Outside ~

Jace slammed his fist over and over again into the wall of the ally beside the Institute. He couldn't even think straight. Except for the pain in his fist, he could feel nothing but the weight of his world crashing down upon him. One word ran in circles through his mind.

"Pregnant."

He didn't realize he'd been muttering it to himself until he heard a feminine voice ask, "Who's pregnant?"

He looked into the face of his adopted sister and inwardly smirked as the pain and torment in his eyes made even her take a step back.

"Clary is pregnant, Izzy."

Her mouth opened and closed like a fish out of water, "You're going to be a father?"

Jace looked at the ground, willing himself not to cry. He remembered his father telling him that tears were for the weak and ground his teeth together before growling out a single syllable.

"No."

Isabelle couldn't believe her ears. "Then who? I thought..." Jace cut her off by telling her the whole story.

As he repeated everything that Clary had told him, he watched her forehead crease with worry.

"So you're going to run out on her? Leave her alone to raise a baby that was fathered by someone that she's no longer with? You're going to give up on anything the two of you could have because she made a mistake by trying to find comfort in someone else when you yourself told her that you were only going to be her brother?"

It was Jace's turn to frown, "How did you know?"

"We women have our ways, Jace Herondale."

"My name," he growled, "Is Jace Lightwood."

Izzy shook her head, "I refuse to call you my brother if you're going to be stupid enough to let go of the best thing that's ever happened to you over a mistake she made trying to get over you. I seem to recall someone else who had a little pregnancy scare with a certain other young Shadowhunter when he was trying to get over the girl who had captured his heart."

These words stopped Jace cold. She was right. He had made the very same mistake with Aline and it had nearly turned out the same way. Before Isabelle could say another word, Jace had run back inside.

When he entered the library, he was hit hard with the sound of sobbing. These weren't just the sounds of someone crying, these were the broken, jagged sobs of someone who had lost their reason for living.

His heart broke knowing that it was because of him that she was like this. Jace had learned quite a lot since he'd met Clary, but it had taken the angry and disappointed words of someone he'd known since he was a child to teach him the most important lesson of his life. Clary was too important for him to throw her away. As long as she wanted him, he'd be here.

He sat beside her on the worn carpet and lifted her into his lap. He heard her sharp intake of breath as he tilted her chin up so that he could look her in the eye.

"Clary." He asked softly, "Do you love Simon?"

Without hesitation she answered, "No."

His eyes softened, though she could still see a glimmer of pain behind them. "Then we will do what we can to take care of this child. Together."

Her breath caught in her throat. "Wh…what? You still want to be with me?"

Jace couldn't help himself. He kissed her for the first time in almost a month. As his hands wound tightly around her waist and hers found their way into his hair, he reluctantly pulled away to reply.

"I've been without you far too long for my liking. I'll stay with you for as long as you'll let me."

That was Clary's undoing. She couldn't hold herself back any longer. She kissed him with all the love and desire that she could muster, putting all of the emotion she'd felt for him for the past six months into the kiss. This time, no one pulled away.