Authors Note: Here's part 4 just like I promised!! I hope you enjoy. I do not have plans for another part right now...perhaps sometime in the future, but not right now. I have an original novel that I'm working on and I really need to update my Twilight fic "Seven" for all of the super patient people that have been waiting since the end of October for an update ;)

Thanks go to Marcy for the beta...a million thanks and Ernie should reward you nicely for being so awesome!!

Disclaimer: TMI and all of the characters belong to Cassandra Clare.

Jace paced across his dark room for the millionth time since he'd hung up the phone. Clary had called very early and asked him where he wanted to meet so they could see what they could make of the rune they'd both tried so hard not to think about since its initial creation. The only place he could come up with was his room; it was set off from the rest of the institute enough to provide them with some small measure of the privacy and the quiet that this little endeavor would require. She asked him to give her 20 minutes—and then took 40. They'd only had a few hours of sleep; darkness still hung heavy outside his window, too obstinate to allow dawn to begin her slow journey across the city from the horizon.

Despite his lack of sleep, Jace's blood thrummed through his veins full of an excitement he couldn't quite understand. He wasn't sure why his stomach had tightened into a knot, clenching at the thought of her quiet knock on the door. It wasn't like anything they were about to do would result in something they couldn't handle or hadn't already done. Perhaps it was because this was planned, because he had time to think about it before it happened. Every other time they'd had time alone it had been completely spontaneous—moments skillfully taken in secret from their family and friends. Hushed encounters in the hallway and careful meetings in rooms they left dark—hurried opportunities to temporarily quench a growing thirst.

Jace glanced at the clock once more and stopped pacing. He let his head fall and his eyes close as he muttered about women and their unpredictability. Two muted thumps on his door caused his head to snap back up; his eyes opened immediately and he combed his fingers through his hair—pushing the golden strands back out of his eyes only for them to fall right back into place once he'd let his hand fall back to his side.

Clary knocked again and he made his way quickly to the door. It was still early and he was worried about someone waking to investigate the noise. He opened the door far enough to grab her wrist and pull her into the room quietly before shutting it again as softly as he could. Just to be safe he locked it manually and marked it with two separate runes: one to ward away curious investigators, and the other to make it difficult to open the door should anyone get past the first. Not only did he not want to be interrupted, but what they were about to do—experimenting with an undocumented rune—wasn't exactly what the Clave would call 'legal'.

Once the door was warded, he looked down at Clary. She stood quietly against the wall watching him with her careful emerald eyes. The only light in the room filtered dimly through the window—the meager offering of city on the cusp of asleep and awake. It glowed against her pale skin and glinted in her eyes as they continued to watch him. It registered to Jace then, that he wasn't the only one that was feeling the gravity of the possible consequences this situation could have without actually understanding them.

She swallowed and wet her lips before pushing off the wall and making her way slowly to his bed. She hadn't brought anything with her with the exception of her stele...what else would she need? She sat on the edge of his bed facing him—he hadn't moved.

"I thought you'd gone back to sleep." She spoke quietly.

"I was about to. You interrupted a very good dream when you called." He smirked, "and you were taking so long—I figured I'd get back to it." He started toward her.

He watched as she fought against a grin that attempted to show itself. She wouldn't let him see that he could amuse her until he cracked first—it was always the same, she had to see a genuine grin on his face before she'd give him hers. This...this was familiar. This was their dance, their game, their love. Humor and sarcasm sparked in the air while they danced around each other until neither could stand it for another minute.

"That good huh?" She leaned back supporting herself with her arms.

"Yeah. Maybe I'll tell you about it sometime—" he paused, "If you ask nicely."

She raised one eyebrow, "You're not going to get me to beg, if that's what you're going for."

He grinned then, unable to ignore the undertone to her whispers. "Never, Clary. I'll never ask you to beg me for anything." She smiled then, because he had.

"Didn't we have something to do?" She sat back up.

Jace sat next to her, playing idly with the stele in his hands. He kept his gaze locked on it, sure that if he met her eyes here in the dark that their plans would be soon forgotten. "Um, yeah. I was serious about that—if we can figure out exactly what's behind that little rune, then we can maybe use it to our advantage."

He looked up at her then, and she nodded in response. It was a slight movement and he could see that she was carefully guarding her expression now. "Do you...remember it?" He whispered.

She nodded once more.

Jace pulled his shirt off over his head in one swift movement and tossed it across the bed. He looked down at the place where his shoulder met his torso, searching for the faded white lines of the little rune. When he'd found it he let his fingers trace quickly over the lines. It felt like it had been years since she'd put it there when in reality it had only been weeks. The memory of how it had affected his thoughts still relatively fresh. He glanced down and saw her hands, clutching so tightly to the bedspread that her knuckles were white. He let his hand fall, covering her tense fingers with his.

"It's alright, Clary." He spoke directly to her now, "There isn't anything to be frightened of. We've done this one before, remember?" He grinned as she finally glanced from their hands on the bed up to his face. "It wasn't that painful was it? As I recall it was pretty da—"

"It's—I'm fine, Jace." She cut him off. "Really. Let's get this over with. I'm tired." She lifted her stele from beside her on the bed. "Do you think it's best for you to Mark me or the other way around again?"

"I have no idea what you were thinking when you created it—I was under a tad bit of stress at the time—so it's probably better, I mean it'll be more accurate for the sake of research if you Mark me again...then, we...I mean we'll be able to see if it, if it has the same, ah...results." He stammered.

"Right." She didn't argue, simply lifted the stele to his shoulder, touching the tip of it to the faded rune already there.

She began drawing it much faster than he'd been anticipating. He jumped a bit, startled by the heat from the tip as she pulled it down along the first pale line of the rune. "Do you know what you're doing? Are you concentrating on the same thing you were last time? What exactly were you thinking last time? Perhaps this isn't the best idea righ—"

"Shut Up, Jace! It's a little late for second thoughts." She didn't lift her eyes from her work. She was right, and if there was anyone in this world he trusted to be marking him with unknown runes, it was Clary. He gave himself over to feeling; taking in the warmth of the stele along with a growing feeling that was somehow both confidence and relaxation at the same time. His eyes fell closed and he listened carefully, trying to discern some of what Clary was muttering. He couldn't make much of it out, but the Mark had him relaxed beyond the point of caring then.

"Clary?" He whispered as the fact that she'd stopped marking him and backed away a bit.

"I'm here." She said. He opened his eyes slowly; gold met green for a long moment. "How do you feel?"

He thought for just a moment before speaking. "I—I don't know. I'm really relaxed, comfortable, there isn't anything in the world that I need to make me happy." The way he spoke almost didn't sound like him.

"But, if you did realize there was something you needed—" She began questioning him.

"There isn't." He interrupted him. His declaration was so finite that it made the concept of not being in need as concrete and solid as the stele she still held in her hand. She put it down next to her.

"I don't think it worked, Jace." She said. "The's supposed to give you the ability to get what you need. It isn't can't need nothing...nobody needs nothing."

"I do...I mean—don't, I don't need anything. Not right now at least." He even gave himself a long moment to just feel and think. There was nothing, he was so completely happy in that moment that he could literally think of nothing that he needed or wanted.

"That can't be right, this was a dumb idea." She stood from the bed. "I'm going home and going back to bed." She started for his bedroom door, slipping the end of her stele into her pants pocket.

"No!" He very nearly shouted. She paused with her back still to him. "Give it a minute...even if it's not working—don't just, leave me."

"Jace, I'm not so sure this was a good idea in the first place." She whispered without looking back to him.

"Well, it's a little late for second thoughts." He mimicked her voice as he threw her own words from earlier back at her. He couldn't stop the grin that spread across his face and from the shift in her hips he knew she'd heard it on his voice.

Jace stood and walked up behind her, wrapping his arms around her and holding her body against his. "Don't leave me." He demanded in her ear. He brushed her hair around her neck and over her other shoulder, exposing her neck to him. Her crumbling resolve showed itself to him as he peppered light kisses along the milky skin there. Her head rested back against his shoulder and she turned her face, letting him take what he wanted. His lips brushed her throat delicately, barely moving. He felt her shiver and it sent a thrill through him.

There it was. That feeling that had consumed him so completely the last time she'd marked him with the rune. There was nothing stopping him from taking what he wanted in that moment. He hadn't noticed it before, because he'd been living with a piece of that mentality for the last several weeks. It wasn't anything new to him this time. He wondered vaguely as he ran a hand up her side and over her shoulder to turn her face towards him, if it would be as diluted for her. His lips made their way to hers and he kissed her slow for a moment. As he tasted her there in the dark, the thought nearly drifted away—a shrinking red balloon against a bright blue sky.

He held on to it, his curiosity only slightly more persistent than his need for more of her.

"Clary," He spoke against her lips.

"Hmm?" Her hand had found its way behind his head; her fingers wound into his blonde hair holding him to her. Her fingers tightened on his hair as she used her teeth gently against his bottom lip.

A low sound forced its way up his throat before he could speak again. "I want to try it on you?" His hand was under her shirt; her stomach was warm and smooth under his fingertips. "Let me Mark you." He spoke against her cheek and ear, unwilling to pull his mouth from her.

"I don't...I'm not—s—sure ," she stumbled, "Jace!"

He paused the attention he'd been giving to the sensitive skin around her ear. "Yes?" He asked, his voice low and layered with want.

"I can't think when you do that."

"When I do what?" He whispered against her ear, "This?" And he let his tongue dart out to trace the shell of her ear. His arm around her midsection tightened automatically when he felt her knees give out. "Or, did you mean this?" he breathed, before taking just the lobe of her ear between his teeth.

The sound that she made then couldn't technically be called a word, but Jace took it to mean, yes.

He backed them up and sat on the bed, settling her next to him. "I want to see if it'll be the same for you."

Her head seemed to have cleared a bit, "But it isn't working for you."

He grinned, "It is." He reached a hand up and tucked her hair behind her ear.

"What do you need?"

"To see if the rune affects you like it affects me."

She hit him. "I'm being serious."

He laughed, "So am I!" Seriousness took over then, "It makes me free to take what I want...and what I want—what I always want—is you. I want to Mark you with it, I want to see if it'll work the same on you."

She seemed incapable of speech. He watched as she opened and closed her mouth several times, but she never actually said anything.


She simply nodded. He reached over and took his stele from the table beside the bed in one of his hands and in the other he took one of her hands. He brought it to his lips and brushed his lips across the curve of her knuckles. Then he opened her hand and kissed her palm, never taking his eyes from hers all the while. Slowly, he made his way up the inside of her arm not stopping until he got to the crease at the inside of her elbow. He caught her eyes again then, "Where? Not somewhere someone might notice."

She shook her head slowly from one side to the other and then shifted beside him. Turning away from him, she reached down and pulled the back of her shirt up, exposing her lower back to him. Jace felt his heart stutter in his chest and then pick up again double-time. He swallowed hard and lifted his stele to the smooth skin of that gentle dip at the small of her back before he lost his nerve. She jumped at first, but then relaxed leaning over a bit more to give Jace room to work. He drew the lines on her back with the careful precision that only a Shadowhunter had. He concentrated while he worked on the feeling that the rune gave him, willing her to have the ability to take whatever it was that she needed. A small selfish and unfiltered place in the back of his mind hoped that she'd need the same things he did.

When he'd finished he reached out a hand and placed it on her back just above the new Mark, and then he leaned over and pressed a gentle kiss to the still warm rune. He leaned back and she sat up, letting her shirt fall back into place, but she didn't turn around to face him.

"Clary?" He questioned quietly as he reached out a hand and placed it on her shoulder.

"Hmm?" She still didn't turn.

"You okay? What are you feeling?"

"I, uh...I don't—I don't know yet."

Jace scooted across the bed, closing the distance between them. He pulled her back against his chest, tucking her head under his chin and wrapping his arms around her. He held her just like that for a while, content to wait—though he didn't recall the Mark taking any amount of time to begin working either time he received it.

After several long moments he felt her shift, turning around to face him. She met his eyes for only a second before she began studying his features. He watched as her eyes darted from his own around his face; lingering on his hair where she reached up and brushed it back from his eyes, around his high cheekbones to his lips. Her fingers traced the slow curving lines on the outside of his mouth and he struggled to keep his breathing even.

When her hand finally made its way back to his shoulder he watched a crooked smile form at the corner of her mouth. What could only be described as mischief sparked in her eyes and he couldn't hold back his own grin.

"What do you want, Clary?"

She chuckled low and short, "Jace." She said as she shook her head back and forth, "weren't you listening earlier?" She leaned in close to him, her lips brushing his ear as she whispered. "What I want has nothing to do with it." She tasted the salt of his skin just below his ear and he couldn't stop the low moan that forced its way from him. "I told you, it only works for what you need."

"What do you—" he swallowed hard, "need?"

She didn't answer him; she simply placed a hand on his chest and pushed. With nothing else left to do, Jace let himself fall back onto the bed. She crawled up beside him, holding her face several inches over his. Her hair fell around them in a curtain of deep red, and he was overwhelmed with the scent of her shampoo as it mingled with her sweet breath. He forced himself to keep his eyes open, unwilling to miss anything that was about to happen.

Shy, hesitant Clary was appealing enough in her own right. Unhindered, bold Clary—Jace had a feeling—would be an experience. He wasn't wrong. She grinned as she flattened her palm against his bare stomach, running it up his chest until it curved around his neck; fingers sliding into his hair. Slowly, and without any extra contact she leaned down, stopping a fraction from his lips. He could feel her breath coming in even measured burst of warm air against his face. He wondered briefly how she was so calm when they were so close. His own breathing had long since become erratic.

He tilted his head and tried to press his mouth to hers, but she pulled away. "Uh-uh." She said. "You wanted to experiment on me, now you've got to deal with the consequences." Without another word she smirked and then moved down his body; pressing her lips to the underside of his jaw, at the base of his throat, to the firm planes of his chest, and over his shoulder. She paused when she reached the Mark she'd put on him mere minutes ago, and used her tongue to trace the dark lines there.

Jace let his head fall back and focused on breathing. It was a lot more difficult than he'd originally anticipated. His fingers were in her hair of their own free will, searching for something to hold on to...he was trying desperately not to fall over the edge he knew me must be teetering on. She stilled, and sat back putting more distance between them than he was comfortable with. Clary reached back and took his hand from her hair, and held it in hers as she lifted a leg over his body and sat; one leg on each side of him. He watched her carefully as her crooked smile made another appearance; she brought his hand to her mouth and ran her nose from the inside of his wrist up his palm. She used the tip of his middle finger to trace her lips before pressing a kiss there.

He made another low sound and tried reaching out to her with the hand she didn't have a hold of. She caught it before he touched her. "I told you this is about what I need Jace." She took both of his hands and pinned them under her own above his head on the bed. She was leaning over him now, her face inches from his once again. "Don't. Move." She breathed over his lips. Her voice was disguised with so much desire—if he hadn't been looking right at her he wouldn't have known it was her speaking.

Jace was more than willing to play her game. He nodded once, holding eye contact with her. She lowered her lips to his then and took his bottom lip between hers. He felt his eyes fall closed as he opened his mouth to hers and kissed her back. She still held his wrists down, which was more than frustrating because all he wanted to do at that point was feel her. His hands balled into fists and he felt her smile against their kiss before pulling away.

She let go of his wrists and sat back again. "You okay, Jace?" She grinned, "Is there anything you need?" He lifted his hands from above his head, "Ah—I said...don't...move."

He drew in a deep breath, and put his hands back where she'd put them; then he returned his eyes to her and waited. She reached down and grabbed the hem of her own shirt, and without hesitation he watched as she pulled it over her head and tossed it to his floor. Her bra was a dusty pink and it matched the flush in her cheeks perfectly. Jace felt the smile spread across his face, and fought with himself to keep his hands where they were. They were playing on her terms...for the time being—and he was interested to see how far the mark would let her take this.

Her hands were on his chest again, they were warm and soft and caused the muscles along his torso to constrict as they passed over. She kept going, leaning down until bare skin met bare skin. He groaned and balled his fists again, his perfectly manicured fingernails dug into his palm. Her lips were on him again; against his throat...along his jaw...around his ear...but never where he wanted them.

Jace struggled to control his breathing and fought to stay still for her; he was rewarded with the taste of her again when she finally made her way back to his mouth. Kissing her when she was this open to it was nothing at all like the hurried kisses they'd been sharing...the kind of kisses where he had to almost convince her to kiss him back. No. This was her kiss...she gave and took only what she wanted...what she needed. She was aggressive and demanding and Jace liked it.

The entire situation was becoming a bit too much for him to handle. With her straddling him, and the way she was kissing him...not being able to move—it was all too much. He shifted under her, lifting his hips; seeking some kind of relief for the want that was coiling tightly in him. She gasped into his mouth and moaned as rocked her hips once against his in return. He squeezed his eyes tight and turned his head, his arms shook.

"Clary." He managed.

"Jace?" She whispered into his ear.

"I can't—" he swallowed hard and wet his lips with his tongue, "I can't do, this...anymore."

"Tell me what you need." Her lips made their way along his jaw again, returning to his lips once more. She kissed him chastely before giving him room to speak.

"I want—"

She pressed her lips to his once more, cutting him off. "Not what you want, Jace...tell me what you need."

He swallowed again and drew in several deep breaths. "I need—" he spoke against her lips, "I need to touch you." He darted his tongue out and tasted her top lip.

"Then touch me." She breathed into his mouth, before putting enough distance between them to look into his eyes.

He gasped in relief and brought his hands down. He ran the back of his hand over her cheek, tucking some hair behind her ear as he watched her eyes. He studied them as he brought his hands to her waist. He watched the barely perceptible changes in them as he ran his hands down her waist and around to the small of her back. He was the only one that could see those changes, he thought, this can't be wrong...what we have no one else has ever or will ever have. He tilted his chin up and pressed his lips to hers again before pulling back. This realization brought him out of cloud of longing that he'd been so lost in before. He marveled at it as he her in.

Jace rolled a bit, so they were both on their sides, legs and arms still intertwined. Both were breathing heavy, and neither was willing to break the eye contact they had. She leaned forward and kissed him again, still watching his eyes. It was slow, and careful...the air around them losing some of the urgency that it had been sparking with only moments before. When she pulled back he sighed and stroked her cheek again.

"I hate the words 'I love you.'" He said suddenly.

She grinned at the random comment that upset the moment they were stuck in. "What?"

"That word—love-- it gets used so much that it lacks meaning anymore."

She nodded slightly, and he thought she must be trying to keep up with him.

"Everyone loves has no more meaning than the word like." He elaborated.

"Oh, yeah." She reached a hand out and stroked his hair.

He sighed again. "It's deeper, right?" he whispered now. "What we have—is deeper than the word, love?" he spit the final word like a curse.

"Jace...what's brought this on all of the sudden?" she asked, "It's not the rune, cause I'm not questioning what we have."

"No, I'm—I'm not questioning what we's just—it's just that it can't be wrong. It's so, so perfect." He ran a fingertip from her forehead down the bridge of her nose to her lips. "It's not like this for can't be." He refused to let the thought pass that it was probably because no one else had that extra special secret bond that he shared with Clary.

"No, Jace." She whispered against his finger, "No one else has what we have." She yawned then.

"You're tired?" he pulled his finger back.

"A bit." She nodded and smiled. He pulled a blanket up over them and she turned around, tucking her back against his chest.

"Sleep." He said settling in behind her. He smoother her hair, listened to her even breathing, and thought. He thought about the complications of their relationship, and about the rune that gave them the ability to forget all about them. He thought about how sure he was that he wouldn't be able to live without her any more. As he thought he ran his finger tips through her hair, down her neck and along the back of her shoulders. He paused when he reached a small star shaped scar on the back of her shoulder. Memories flashed through his mind; Clary talking about covering a scar with a tattoo, them in the training room...he saw it, and then had forgotten all about it. His hand left her scar and traveled to his own...shaped exactly the same. After some sleep, he thought, he would look into what might cause a scar like that...because he was suddenly sure that Clary's hadn't been a result of the chicken pox like she'd been told.

But for now, he needed sleep. He wrapped his arm back around her and laid his head just behind hers; letting the soft scent of her hair and steady breathing coax him into unconsciousness.