Disclaimer: I do not own Shadowhunters or any of the characters featured.

Note: This story is set after episode 2x16. Warning, there are a few spoilers for this episode.

Alec walked swiftly down the grand corridor of the New York Institute, completely focused, not noticing his sister Isabelle as she approached. Dressed typically for her in a sexy black leather dress and high heeled boots, Isabelle startled Alec when she grabbed his arm to gain his attention.

"Hey Alec, what's the emergency. Is everything ok?" she asked.

Alec had that thoughtful frown he often wore as if the weight of the world was on his shoulders, or at least that of New York, she supposed, now that Jace had officially made him head of the Institute, where the three of them and their younger brother Max had grown up.

"Erh yeah" he replied distractedly. "Have you seen Jace recently? ...I just wanted to check he's OK."

Worry blossomed in Isabelle's chest. She'd seen Jace a while ago and he hadn't mentioned anything. He'd seemed tired but that was all and she'd assumed he'd just been missing out on his beauty sleep lately due to recent events involving a certain red headed shadowhunter.

"He was headed to the training room about an hour ago" she informed him. "Why. Is something wrong?"

Alec gently pulled his arm free, absently touching his side where his parabatai rune was hidden under his black sweater. "It's just...its nothing...I've just got a weird feeling" He said, finding it difficult to explain. "I just wanted to go check on him that's all."

"What do you mean weird? Do you think somethings happened to him?" Isabelle asked concerned now.

"No, no" he said, "it's just... It's fine, I'm sure it's nothing." He didn't want to worry her.

Isabelle let him go as he began to walk off. "Ok" she called after him. "Let me know if you need anything?" she said feeling troubled now, but Alec was no longer paying her any attention.

...

Jace felt like crap. There was no-one else in the training room when he'd arrived, which had probably been a good thing considering the way he was feeling. Why he'd thought working out today would be a good idea he'd never know. He had hoped it would provide a distraction from the headache he'd woken up with this morning, but it had steadily gotten worse as the day had dragged on. Now he could no longer ignore the constant pounding inside his skull and he didn't seem to have the energy to do anything. The iratze he'd tried earlier had given him little relief and now he was here he just felt awful, so hot and sweaty and his headache worse than ever.

He tried to pushed on regardless, but soon found himself leaning against the ornately plastered wall as he rode out an unexpected wave of dizziness. He groaned feeling sorry for himself clutching his stomach gently as it revolted against the swaying room around him.

Could he possibly feel any worse he thought.

After a minute the feeling that he was about to throw up all over the scratched wooden floor below him had passed, however the effort of standing was fast becoming a chore. The seraph blade in his right hand, which usually felt like an extension of himself, seemed to have grown heavier since he started training and he let it slip to the floor with a clatter that reverberate through his head. He squeezed his eyes shut in response and massaged the bridge of his nose to relieve the constant throb that had taken root there.

He didn't need this today. His week had sucked already with everything that had happened with Valentine and the cabin. Not to mention the situation with Clary. He'd felt so weary all morning. He let himself slide boneless down the wall onto his haunches, his legs flopping out in front of him. The bright chandeliers hanging majestically from the training room ceiling were hurting his eyes and all he wanted to do was crawl back to bed and curl up, but he suddenly felt too exhausted to move.

He sat there, quietly for several minutes riding it out, but despite this his headache etched up a notch and the pain made him want to cry out. He pressed his palms into his eyes to push it away as a shiver swept through his body despite the sweat beading on his forehead. Great now he was cold, he thought hugging himself. He'd had enought. It was time he went and got something for the pain and went to lie down. Resigning himself he slowly pushed himself up as another wave of dizziness hit and threatened to drop him back to the floor. With it the nausea returned with vengeance and he thought he might actually throw up this time.

He staggered over to a small round table and chairs in the corner where he and Alec would sometimes talk after sparring together and gripped the backed of one of the chairs for support. His arms were trembling lightly with the effort as he stoosd panting heavily, waiting for his stomach to settle. By the angel, his head felt like it was going to explode. He let out a low groan and with a sigh of defeat, collapsed down into the chair, resting his head on the table. It's surface was cool and soothing on his warm skin, and he buried his head under his arms to escape the harsh light. Absently he wondered where Alec was, wishing he would come and find him. He was beginning to think he would definitely need help getting back to his room so he could sleep through whatever this was.

...

Jace didn't hear it the first time Alec called his name. He had no idea how long he'd been lying there and he felt detached from his body except for the constant thrum of the pain. However as he began to focus on his surroundings again he became aware of someone else nearby. Slowly he registered his parabatai's face. Alec had come like he wanted. Self-consciously he realised that Alec would be worried seeing him like this, looking like he didn't have the strength to move, which was exactly how he felt, so he an made effort sit up to show him he was ok. But once he was upright he felt like he was drifting and his headache seemed to intensify again. His brain didn't want to engage and without thinking he leaned into his brother to ground himself burying his face into his chest to block out the light. He just wanted the pain to go away. He couldn't remember ever feeling this bad.

There were more voices now but Jace could no longer focus on anything outside of the pounding in his head to care.

...

The training room was deathly quiet when Alec walked in and he was felt anxious that he'd missed Jace. However, as he started to take his phone out to try calling again he noticed a hunched figured at the small table in the corner of the room partially hidden behind a rack of training equipment. He approached quickly eyes settling on ruffled angel gold hair that he knew could only belong to his parabatai. Jace looked asleep, slumped forward across the table with his right arm covering his face and it was very obvious something was wrong with him.

"Jace" he said quietly.

When he got no response, he pulled out the adjacent chair and perched on it close to his brother. He gently shook Jace's shoulder to gain his attention trying not to startle him and called his name again, louder this time.

"Jace!"

This time Alec was rewarded with a slither of glassy eyes as his brother sluggishly turned his head to glance up at him. Jace looked exhausted. He frowned in obvious discomfort and worryingly let his eyes slide closed again without answering.

"Jace, hey you ok" Alec asked as he brought his hand up to rest gently on Jace's forehead, surprised at the heat radiating from his clammy skin.

"You're burning up" he stated, his brow creasing in concern.

At this Jace seemed to muster some energy taking hold of Alec's hand to help pull himself upright so that they were facing closely.

"Just got a headache" he said huskily.

It was obvious to Alec that Jace was feeling dizzy too. His eyes blinked slowly and he maintained a tight grip on Alec's hand as he seemed to wait for his equilibrium to returned to normal.

Alec highly doubted it was 'just a headache' as he examined Jace more fully. He brought both hands up to grip the unsteady looking shadowhunters upper arms in support, but surprisingly Jace swayed forward to rest his forehead on Alec's chest. For a brief moment Alec's heart jumped as familier desires he'd developed over the past few years, before he realised what love felt like with Magnus, flashed into in mind. They were quickly forgotten though as Jace spoke, his voice muffled by Alec's jumper. "It hurts Alec. I need something for it". Automatically Alec wrapped his arms protectively around Jace as he slumped further into him clearlyvno longer having the energy to support himself.

At that moment Isabelle and Clary walked in, expressions mirroring concern as they caught sight of the two brothers. Isabelle had most likely told Clary about Alec being worried and immediately followed him here.

"Jace " Clary whispered, hurrying across the room, her boots thudding loudly on the wooden floor.

"Alec what's wrong? Is he ok?" Isabelle inquired joining them.

"I don't know Iz, he's sick. He says it's just a headache but I don't think so. He feels really hot."

Alec reached in to brush Jace's sweaty hair aside so that he could see his face. "Jace, hey come on, let me look at you," he encouraged, but Jace didn't respond. He met his sister's concerned eyes. Jace would normally hate people seeing him like this. He wasn't doing so good he thought. Help me lift him so I can activate his iratze" Alec asked the girls, trying to stay calm. But as Isabelle and Clary eased Jace away from him, Jace let out a panicked groan grasping out for Alec's jumper trying to steady himself and it took a few moments for awareness to replace the pained, confused expression on his pale face.

"Hey, Jace it's ok. You're ok." Alec soothed, cradling his chin with one hand to help hold his head up as Jace looked groggily between his fellow shadowhunters. His eyes slowly came to rest on Clary as she captured his attention.

"Clary" he slurred.

"Hey it's ok" she said brushing his hair gently back from his face. " Just relax ok."

Jace's eyes drifted closed again and he didn't seem to notice as Alec took out his stele and lifted his white t-shirt to expose the healing rune on the right side of his abdomen. He let out a low groan as the rune glowed dully with the stele's touch and his siblings exchanged worried glances when it became obvious it was making no difference.

"We need to get him to the infirmary" Alec stated.