A/N Hello! 3+ Comments and 3+ Votes for the next chapter! :)
Also, 15k reads? That's insane! Thank you guys so much!
Just a heads up, this chapter is all over the place because it's the Alternate Universe episode! It was kinda fun to write though aha :) 
Again - Not edited! 

*****
'I need to get back to the institute, talk some sense into Alec.'

Clary looked sideways at Jace as he shifted uncomfortably. 'What?' She questioned in suspicion, drawing Isabelle's attention.

'I uh, I didn't realise Adelaide was there. She knows about Alec's engagement.' Jace looked down, guilt settling heavily in his stomach.

Isabelle visibly paled. 'Oh no. No, I was supposed to talk him out of it. She wasn't supposed to find out.'

'I didn't know she was there. She was still in there with him when I left.' Jace glanced at the girl he considered family. 'You should have seen her face.'

'This can't be good.' Isabelle whispered.

'Does he love her?' Clary asked with dawning realisation. She'd seen the signs of course, but she hadn't been sure, not until now.

'I'm not sure even Alec knows the answer to that.' Jace admitted, still feeling the sting of betrayal from Alec's actions. Unconsciously, Jace reached out to Alec through the parabatai bond, feeling the crushing sadness and quickly withdrawing.

Alec was hurting.

Adelaide was hurting.

Everything was one jumbled mess of misplaced anger and regret.

Isabelle gave Meliorn one last kiss as she left, heading back towards the institute. Meliorn watched her go with a smirk on his face.

'Isabelle told me it was your idea to rally the downworlders. That you spear headed my rescue.' Meliorn looked to Clary who looked embarrassed.

'Don't give me too much credit, Isabelle made this happen, we just helped.'

'She's being modest.' Jace interrupted. 'You're a shadowhunter now.' He looked at Clary.

'I have been surprised by more than one shadowhunter tonight.' Meliorn admitted. 'You risked everything to unite us.'

'Right after you tried to sell her out.' Jace reminded him.

Meliorn looked regretful. 'Not my finest moment. Which is why I'm offering you a gift for your sacrifice.'

Clary and Jace looked wary.

'If you're ready, I can help you find your father.'

Adelaide heard Meliorn's statement as she rounded the corner. 'Well well well Meliorn, looks like you know more than you told the clave.'

Meliorn smirked at her. 'Adelaide Renhallow, surprised to see you around considering most of the shadow world thinks you died.'

Adelaide scoffed. 'Cut the act, Meliorn. You know exactly who I am.'

'Valentine's daughter.' Meliorn smirked. 'You're right, I do know.'

Adelaide smirked back at him. 'Now, what do you know about our father?'

*****

'Where the hell have you been?'

Isabelle rolled her eyes as Alec approached her, looking sterner than usual.

'Exactly where I needed to be, away from you and your fiancé.'

'Jace and Clary are on the run.' Alec warned her. 'I can't protect you if you don't tell me the truth.'

'I don't need protecting. Meliorn's alive, and that's all that matters.'

'Just, hey-' Alec grabbed Isabelle's arm as she went to walk away, he sighed. 'Just tell me this, is there any way that Raj could have seen anything incriminating?

Alec glanced at Lydia, who was interrogating Raj who looked at a loss as he tried to explain what happened.

Isabelle stared at her big brother. 'No. Now answer a question for me. What did Adelaide say to you?' Isabelle's voice lowered.

Immediately, Alec's throat seemed to close as he looked away from Isabelle's searching eyes. 'Nothing.'

Isabelle sighed angrily. 'Do me a favour Alec, stop lying to everyone.'

*****

'We'll be extra careful then.'

Adelaide saw the amusement creep into Meliorn's expression and she knew immediately that she wasn't going to like what was coming. They had made their way to the outskirts of seelie and Adelaide was feeling exposed, something she didn't like at all.

'There is no we in this scenario. Only Clary goes in to find the portal. My debt is to her.' Meliorn's reply was short.

Adelaide rubbed her eyes tiredly as Jace narrowed his eyes. 'You've given us no reason to trust you, seelie.'

'He brought us here.' Clary countered Jace's argument and Adelaide smiled slightly at her younger sister's mischievous reply as Meliorn began establishing a connection to the other realm.

'What's it like? This other dimension?' Adelaide asked to break some of the tension that was forming. 'Is it like this one?'

'It is, but it isn't. It's an alternate timeline in a sense. There, shadowhunters and demons no longer exist. The shadowhunters won the war against the demons centuries ago and the downworlders that are left have conformed to a mundane way of life to avoid detection.' Meliorn replied casually.

'What will happen to the Clary in that dimension when this Clary goes in?' Adelaide questioned suspiciously.

'She will think and feel, just like her.'

'I'll still know I'm me right? I'll know to find the portal?' Clary questioned nervously.

'There's a catch. With seelies there's always a catch.' Adelaide didn't look away from Meliorn's smug expression.

'Your alternate self could consume you if you let it.' Meliorn admitted.

'Of course.' Adelaide muttered, sighing as Jace looked at Meliorn sharply.

'Can't just be a simple in and out can it.' She muttered under her breath.

*****

Darkness had begun to fall and Adelaide was pointedly ignoring Jace and Clary's whispers and romantic gazes.

'Not a fan of PDA?' Meliorn questioned her as he stopped waving his hands around.

Adelaide snickered. 'Not at all.'

'Perhaps you just haven't met the person who'll make you want to be that way.' Meliorn gestured to Jace and Clary. 'There is hardly anything shameful about showing your emotions.'

Adelaide ignored him and he sighed.

'It's time.' He announced.

Adelaide listened silently as Jace and Clary convinced Meliorn to allow Clary to come back for them after she found the portal.

Adelaide watched with interest as Meliorn began speaking the seelie language as the iron door unsealed itself and Clary stepped forward.

'Be careful, Clary.' Adelaide called as Jace stood beside her.

Clary nodded and then she was gone.

*****

'Where's my mother!' Clary held the knife out in front of her, anger and panic filling up her chest.

'Whoa.' Valentine laughed. 'Is this from one of your cosplay skits? Uh, honey come in here you gotta see this.' He laughed again. 'No seriously you have to let me come with you, just once, okay? I want to see what you do at these things alright?'

'Val, you're not allowed to do cosplay. You'd stick out like a sore thumb!' Jocelyn laughed as she entered the room.

'Mum!' Clary hugged her mother who laughed.

'Wow, if you miss us this much, you should really leave the dorm room more often.'

Clary laughed nervously. 'Right, sorry.'

*****

Alec was tapping at the security systems on the screens in the institute when a head of blonde hair stopped at his side. 'I'm sorry.' She looked regretful and nervous all at once.

'For what?' Alec questioned incredulously, watching as Raj stopped behind Isabelle and Lydia made her way to his sister.

'Isabelle Lightwood, by order of the clave you are under arrest for high treason.'

'What? On what grounds?' Alec questioned incredulously as he followed Lydia.

'Only a handful of people knew about the Meliorn op.'

'And everyone knows she's sleeping with him.' Raj added and Isabelle smiled sarcastically at him.

'You know what Lydia? You're no better than Valentine. But at least he had the guts to tell Downworlders to their faces he wanted them all dead. You hide behind the law.' Isabelle was seething with rage.

'I don't hide behind it, Isabelle. I simply follow it, because it guards against one very important thing. Shadowhunters fighting other shadowhunters.' Lydia shot back, anger in her voice.

'If she's convicted she'll be stripped of her runes and banished. I can't let that-' Alec tried to defend Isabelle as she handed her stele to Raj.

'Don't.' She stopped Alec speaking. 'It's not your fight.'

Raj led Isabelle away and Alec stormed off, unsure of what to do next.

It seemed he'd lost nearly everyone he cared about, and now, he had no one to turn to.

*****

'Hey! Where've you been? We've been texting you for like twenty minutes!' Clary turned and found Simon smiling at her, his familiar glasses back in place on his face.

'Simon, get out of the sun!' She warned instinctively.

'Hey, what the hell?' Simon gave her a weird look and Clary quickly realised that, of course, Simon wasn't a vampire here.

'I know that look.' He smirked. 'Caffeine deprivation. Come on.'

Clary's mind struggled to keep up with what was happening and suddenly she was standing at a table with Alec and Isabelle while Simon went to get her coffee from a van with the name Java Jace printed across the side.

'Is that new?' Clary looked down at her necklace before looking up at a vastly different looking Isabelle, who was wearing thick glasses and a star wars shirt.

'Yeah, I got it a couple of days ago.' Clary lied.

'Oh, it goes with your dress? Because you're getting ready at my place tonight, right?' Isabelle smiled cutely.

'Ready for what?' Clary questioned hesitantly glancing at Alec, who was wearing dark jeans and a dark shirt, no trace of a scowl in sight.

'That's not even a little bit funny.' Alec leant back in his seat, stretching as though he'd been sitting for a while.

'What?' Clary questioned with wide eyes.

'Adelaide has poured her heart and soul into this anniversary party, and the theme is amazing.' Alec mocked as Isabelle slapped him lightly.

'No, but seriously, don't let Adelaide hear you questioning anything. Trust me, I learnt the hard way.' Alec rolled his eyes, but shot a smile at Clary.

'Where is Adelaide?' Clary questioned, wondering what this universes Adelaide was like.

'Picking up decorations or something, I can't keep up.' Alec glanced at his phone screen as Simon reappeared. 'But seriously, what is with this guy and the mad hatter?' He questioned his sister.

'Visionaries are quirky crazy. You don't get 4D technology thinking inside the box.' Isabelle replied, staring at her brother with a raised brow.

'I'm beginning to wonder if you don't have a thing for your boss.' Alec smirked as Isabelle flushed.

'Like, as if Clary and Adelaide's Dad would ever go for me.' A dreamy expression crossed Isabelle's face.

'My Dad?'

'Uh, no, I'm totally kidding.' Isabelle scoffed as she avoided Clary's eyes. 'I mean, I'm not crushing on your dad, right? No.'

'Right, of course not. That's be totally weird.'

'Yeah.' Alec looked at his sister in amusement.

'We're setting up at six right?' Simon questioned Alec, who nodded in confirmation.

'I need your help tonight, this gig could be huge for me.' Simon smiled at Clary.

'Hey.' Jace appeared. 'Wanna get out of here.'

Clary smiled dreamily at him. 'Sure.'

Isabelle watched as they walked away. 'They can't keep their hands off of each other can they?'

Simon snickered. 'Give it time, they'll be married or having a kid or something.'

'Can you imagine Jocelyn and Valentine's reaction?' Alec laughed lightly.

'Yeah, can you?' Isabelle smirked knowingly to herself.

*****

'On a scale from one to namaste, how screwed are we?' Jace questioned as he looked around warily, Adelaide by his side as Meliorn informed them of the coming attack.

'Demon's are attracted to this dimension, it's defenceless and peaceful. They like chaos and havoc.' Meliorn explained.

'Alright pointy ears, looks like yoga time might be over.' Adelaide laughed at Jace's words.

'Hope you've been training Adelaide.' Jace muttered.

Adelaide scoffed. 'Please, I could still kick your ass, trained or not.'

Jace scoffed.

*****

'You hope he is your soul mate, but secrets revealed will threaten to tear you apart.' Clary's vision blurred slightly and she jumped as a cat leapt up in front of her.

'You don't have a cat.' She spoke more to herself than to Magnus who looked at her curiously.

'I have two. Chairman Meow and Church.'

'I'm not actually here for a reading; I know you're a warlock Magnus. I'm a shadowhunter.' Clary admitted as Magnus laughed.

'There are no more shadowhunters. Haven't been for hundreds of years.'

'I can prove it.' Clary jumped up to show off her runes.

'All I see, shadowhunter, is that you could use a tan.'

'Right, bad strategy. No runes in this dimension. I'm from an alternate reality.' Clary explained quickly.

'If that were true, without an anchor you'd be assimilating into this world.'

Clary scoffed. 'Believe me, I am trying to fight it. Which is part of why I need your help.' Clary showed Magnus her drawings of two demons. 'In my dimension, shadowhunters still battle demons and now there is something so much worse, and I need your magic to help me stop it.'

'I can't help you.' Magnus sighed regretfully. 'My magic's gone dormant.'

'Then wake it up.' Clary begged.

Magnus stared at her.

*****

'I may have something the clave wants.' Alec admitted quietly as he stood in front of Lydia. 'I can give them the mortal cup.'

He'd run out of options, and there was no way he was letting his sister be banished and stripped of any runes she possessed. Alec had no choice but to hand over the mortal cup, even if it meant Jace being livid with him.

Lydia's eyes widened. 'Alec, you have it? Why didn't you tell me before?'

'I promised Jace, and there's this thing with Clary it's-' Alec tried explaining.

'I get it. He's your parabatai.' Lydia nodded in understanding and for that, Alec was thankful.

'I'm gonna trade the cup for Izzy's freedom. Do you think the Clave will go for it?'

'To keep it out of Valentine's hands they'll do anything.' Lydia sounded excited. Despite what Isabelle thought she took no joy in locking her up. 'Where is it?'

Alec motioned for Lydia to follow him as he undid the hidden compartment in the institute floor. Alec cursed when he noted the missing items.

Lydia looked confused, staring up at Alec's angry face. 'Jace.' He spat in answer to her unspoken question.

Alec headed straight for the room Isabelle was being kept in.

'Keep it short.' Raj warned but Alec ignored him, crossing his arms as he walked towards his sister.

'Jace stole the cup.'

Isabelle looked unsurprised as she refused to meet Alec's gaze.

'Izzy, did you know about this?' Alec questioned incredulously. 'My god, did you help him? The cup is the only thing that can get you out of this.'

'Jace is doing what he thinks is right.' Isabelle responded simply.

'What's right? He put the whole shadow world in danger, he put you in danger. We have to get him back here, with the cup. It's the only thing that can help you.'

'They've taken Meliorn back to the seelie realm, you can't track him there.'

'Not by any of the normal ways.' Alec made his way to the door, an idea forming in his mind.

Isabelle gasped. 'No, absolutely not. You cannot track Jace through your parabatai bond. It will weaken both of you, or break the bond.'

'Jace already weakened it. How does he think I can trust him after what he did?'

'Don't say that. Please, Alec. Think about what you're doing.' Isabelle begged, but Alec ignored her as he left the room, shutting the door behind him.

*****

Isabelle was ranting about her black eye as Clary watched, wide eyed at the usually calm and collected Isabelle so panicked over something as simple as a bruise.

'-And then Adelaide worked so hard to plan this, I just cannot not go to the party. What am I supposed to do-'

'Hey-'

'I worked so hard-'

'Hey, We're gonna fix this.'

'Okay.' Isabelle gave in. 'But then we have to fix you and Jace because the two of you not talking really messes with my chi. Are you sure those are the colours?' Izzy questioned nervously.

'We'll make it work.'

'Okay, because if I don't show up to the party, your dad and Simon are so gonna kill me. Not to mention Adelaide.'

'So um, you think you could get a friend of mine on the guest list for tonight?' Clary tried to sound casual.

'If you make this work, I'll do anything for you.'

*****

'Clary!' Clary whirled around at the familiar voice.

'Adelaide.' Clary looked at her sister, whom was wearing a gorgeous red dress, as she made her way towards where Clary was standing.

'You look cute. How's Jace?' Adelaide questioned as Alec appeared beside them.

'She wouldn't know. She ran away from him today.' Alec looked pointedly at Adelaide who gave him an amused look.

'Clary, we've talked about this! You two are so good together. You don't have to play hard to get.'

'I-I'm not-'

'Trust me little sister, it's much better to just be honest.' Adelaide glanced sideways at Alec who smirked.

'Adelaide!' Jace came towards the trio.

'Hey there blondie!' Adelaide hugged Jace who hugged her before pulling Alec in for a bro hug.

'May I?' Jace held out his hand to Clary.

'Jace, Hi, um-'

'Clary, what's going on?' Jace frowned, looking at Adelaide who shrugged.

'Uh oh, parent alert Clary.' Adelaide warned in a low voice.

Jocelyn and Valentine were making their way towards them, Jocelyn looked apologetic and Valentine looked confident while both Jace and Alec tensed slightly.

Adelaide let her Father interrogate Jace and a very different Clary as she spotted Isabelle and Simon coming towards them. 'Hey lovebirds!'

Isabelle flushed and Simon grinned. 'Hey Adelaide.'

'You look stunning.' Isabelle squealed as the two girls embraced.

'Both of you, come over here for a second, yeah?'

Jace was nervously stammering much to Valentine's amusement. Adelaide decided to put him out of his misery by interrupting as she stood next to Alec, squeezing his arm reassuringly as he shot her a nervous look.

'Hey guys? There's something I wanna say.' Adelaide interrupted the conversations.

The small group all turned their eyes towards Adelaide expectantly. 'I just wanted to say uh –' Adelaide laughed nervously and Clary's heart rate picked up.

Alec cleared his throat nervously, entwining his hand with Adelaide's own.

'We're engaged. We're getting married.'

There was a split second of silence until Isabelle squealed, attracting some attention from other guests. She pulled Adelaide into a hug. 'I knew it!'

Clary felt herself being pulled into the hug as well. 'We're going to be sisters!' Isabelle chirped excitedly.

'Yeah, we are.' Adelaide laughed, her happiness unmistakable.

'Guess we have to put up with each other now, huh?' Alec spoke quietly to Clary once Isabelle had released her.

'I guess so.' She nodded at him and he laughed.

Clary watched as Alec made his way back to Adelaide, wrapping an arm around her waist and kissing her head gently as she relaxed into him. Clary had never seen the Alec and Adelaide she knew look so happy and content in the time that she had known the both of them, and for a split second she wished that the two people she knew back at home would finally get their happy ending too.

But in the real world - her world - happy endings were few and far between.

*****

Adelaide and Jace were skilled warriors.

Together they fought almost as well as they fought with their own parabatai. Adelaide had Jace's back just as he had hers and it showed as they fought the demon away from the open portal. The demon swung at them again, Meliorn fighting beside them.

Jace was ready to place the final blow when, out of nowhere, Jace stopped suddenly holding his midsection in obvious pain.

'Jace?' Adelaide called warily.

The demon seized the opportunity that had presented itself and knocked Jace back and Adelaide rushed at it, her seraph blade drawn, only to be hit backwards as well.

'Alec!' Jace yelled and Adelaide's blood ran cold.

Adelaide got up again, rushing towards Meliorn who was knocked out of the way by the demon whom promptly entered the unguarded portal.

'No!' Adelaide screamed, hurrying to follow it before she was tugged back by Meliorn who shook his head. 'Trust me Adelaide, if you go in there, you'll become her. Once you see what's inside, you won't want to come back.'

Adelaide looked at the seelie curiously but Jace groaned in pain again and she hurriedly knelt beside him. 'Jace, Jace what's happening?'

'Alec-' He yelled again, before his writhing promptly stopped and Jace fell into unconsciousness.

It wasn't long before Jace was back on his feet as Meliorn woke him up, sensing more demons coming. Adelaide steadied Jace as he told Adelaide and Meliorn his plan.

'Let me come with you.' Adelaide spoke to Jace, ignoring the look Meliorn sent her.

'No.' Jace shook his head. 'It's too dangerous. I need you to stay here, do whatever you can from this side.'

Adelaide swallowed. 'Text me when you're safe, please.'

'You should go.' Meliorn warned Jace who nodded.

'Jace? Take care of my sister.'

Jace smiled at Adelaide. 'Always.'

Adelaide nodded at Meliorn as she disappeared from sight, becoming one with the shadows once more.

*****

'What happened? Are you and Jace okay?'

Isabelle questioned her brother the second her walked back into the room. She could see the weariness in his face and she felt a stab of sympathy for him. It had been a hard year on all of them, especially Alec.

'No.' Alec sighed. 'Our parabatai bond, it's just so weak. He's like a ghost.' Alec admitted as he sat on the couch.

Isabelle's shoulders slumped. 'My bond with Adelaide is the same. Except, I guess she really isn't there anymore, not after her and Magnus severed it as best they could. Alec, why would you intentionally hurt Jace? What did you do?'

'Lydia and I thought we could stop the trial if we gave the cup to the clave.'

'Lydia helped you?' Isabelle asked in surprise.

'It doesn't matter. She has no choice but to go through with the trial now.'

'It's okay big brother, I know you tried.' Isabelle wrapped an arm around her brother gently, even though her heart sank at his words.

Alec closed his eyes as he leant his head against his hands. 'I'm sorry.'

A few minutes later, Alec spoke again. 'I screwed up, Izzy.'

'What do you mean?' Isabelle frowned.

'You told me to talk to Adelaide, to find out what happened that night and I didn't. She finally told me the truth last night...she saved my life.' Alec's voice was low and he didn't look at Isabelle as he spoke.

'Oh Alec...'

'I owe her everything and now she can't even look at me.'

'She loves you Alec. She always has.' Isabelle spoke gently. 'It'll be okay. The two of you will talk it out and-'

'I'm getting married.' Alec choked out in response. 'I'm marrying Lydia.'

'Alec-'Isabelle started, her voice softening at her brother's obvious distress.

Alec squared his shoulders, putting on a brave face. 'I uh, I have to send word to our parents. I'll find a way to fix this.' Alec swallowed thickly as he stood up, almost running to the door, ignoring Isabelle's protests behind him.

Isabelle had a way with words and Alec knew that if he stayed there for one more minute, she would have had him calling off the engagement to Lydia and seeking out Adelaide in an instant. And no matter how tempting the idea was, Alec couldn't do that. Where his family was concerned Alec couldn't afford to be selfish, and he'd do whatever he had to in order to keep them safe.

Even if it meant sacrificing his own happiness in the process.