Disclaimer: I don't own any of the characters from Shadowhunters or The Mortal Instruments series they belong to Cassandra Clare. I do own characters that I create.

A/N: Short prequel to "A Love Like No Other"

Wondering what I was talking about in "A Love Like No Other" when it was said that Agatha's existence was hidden from Jace, Isabelle and Alec? Well look no further.

Miss You More

Agatha Wayland, older sister to Jace Wayland – was adopted into the Lightwood family at the same time as Jace. Though she had known Alec for as long as she could remember. Ever since she was little Agatha had been able to disappear to fragments in time and see things that she should see.

"Hey Alec," Agatha grinned, looking at the twelve-year-old and giving him a hug as they both watched Jace trying to impress Maryse. "Come with me, I need to ask you something,"

"What Aggie?" Alec questioned, following after the thirteen year old leaving Isabelle and Jace vying for Maryse's attention.

"I need to go away, and I want you to promise me something," Agatha told him, as they stood in the green house away from prying ears.

"Why do you have to go?" Alec questioned, looking her in the eyes.

"You know how I have both downworlder and nephilim blood? Well the downworlder side is coming stronger...and Magnus...Magnus Bane promised me that he would train me to use them," Agatha told him as calmly as she could for a slightly scared and excited teenager. "My Uncle Luke said he'd look after me too at least for a little while,"

"But what about Jace?" Alec questioned thinking of younger best friend as he spoke. "And Isabelle?"

"I'll be back, I promised Isabelle that she would be my parabatai. And Jace...well he's going to hate me for leaving him," Agatha sighed, her baby brother was soon to be ten years old as was Isabelle.

Maryse had come to stand in the doorway of the greenhouse and had heard everything that Agatha had been telling Alec. She understood the connection between the oldest of the two children. Alec would do anything to make Agatha happy and she anything for him.

"Agatha, he has agreed to do it," Maryse interrupted the children from where she was standing. "Come now, Jace and Isabelle are waiting,"

"Aunt Maryse, can you let me give Jace what I drew for him?" Agatha asked as her and Alec made their way to her. "And, can you make sure that it's always in his room?"

"Agatha, hurry and do it and then we must leave," Maryse had reluctantly talked with Magnus Bane and he had agreed to temporarily erase Agatha from the memories of the Lightwood children.

"I have something else for Izzy and Alec," Agatha hurried off to her room to grab the things that she had in place for Alec and Isabelle.

As soon as she arrived in her room Agatha had found exactly what she was looking for. She found a leather bound wristband that she had put 'A & A Bestfriends For Eternity' on for Alec and for Isabelle she was giving her, her favourite toy. Once she had grabbed everything that she needed from her room she ran back to where Maryse was waiting for her with Alec, Isabelle and Jace.

"Izzy, this is for you," Agatha smiled handing the ten year old a battered and teddy bear. "I have to go away for a little while and I want you to look after him I know you play with him when I'm in Idris,"

"No I don't!" Isabelle grinned as she hugged the teddy bear tightly.

"Very funny Isabelle," Agatha hugged her just as tightly as Isabelle was hugging the bear. "Alec this is for you, hold out your hand," Agatha turned to Alec with the leather band in her hand and wrapped it around his wrist. "Isabelle, I'll be back in two years and then we'll be parabatai's I promise you that,"

"What's this for?" Alec questioned, looking at it closely and seeing the small letter engravings on it.

"You'll know when it's time," she hugged him as well before turning to Jace who was starting to walk away from her. "Jace, come here. I haven't forgotten you," Agatha grabbed hold of Jace's arm before he could get too far.

"Don't go Aggie, please!" Jace all but cried as he looked at her, he was trying to be strong but it was hard being an almost ten year old and being told that your big sister was leaving.

"Jace, I have to. I know it will be hard but Alec will always be here for you, and I'll come back soon I promise," Agatha was still trying to be strong herself. "This is for you, I want you to keep it somewhere safe in your bedroom." Agatha handed Jace the picture she had drawn him and watched him open it before running off to his room to place it in a safe place and returning just as quickly as he had disappeared.

"Children, guard your emotions please," Maryse looked at the four children before her and then motioned for them to follow her.

The four children followed behind Maryse, Isabelle grabbing tightly on Agatha's hand she didn't want the older girl leaving them. None of them did. Jace had grabbed her other hand while Alec had walked a little behind them. They followed Maryse to Magnus' lair where they were told to go in and she would way for them outside.

"Magnus!" Agatha grinned running towards him and wrapping her arms around the warlock.

"Now, now little sister are you sure that you want to do this?" Magnus questioned looking down at her as he spoke and then towards Alec, Isabelle and Jace.

"I'm sure, they can't remember me...make the first wear off in two years when Isabelle's twelve I promised her that we'd be..." Agatha trailed off as she received a warning look from Alec who shook his head. "Forget what I promised her, just make it last till she's twelve,"

"Okay, but when you turn fifteen you're helping me as you'll be able to do this mostly yourself, you've already progressed so far in your thirteen years of being alive," Magnus told her, and then motioned for her to stand with the others. "The three of you please stand with your hands joined around Agatha, this won't hurt a bit," Agatha glanced at both Magnus and Alec.

"It will be okay, I promise you'll see me again soon," Agatha told them and with that Magnus' hands started to spark purple as he cast the spell that would temporarily erase Agatha from the minds of younger siblings.

After Magnus and Agatha were certain that the spell worked they guided the three children back outside to where Maryse was waiting for them with Luke. Alec looked back at Agatha as they started to walk away from them, a small smile on his face which quickly disappeared as his mother looked at him.

"Magnus...did you change it when you said Alec's name?" Agatha asked watching as her family walked away from her and looking between Magnus and Luke.

"Never you mind, now off you go with Lucian, the spell will wear off with in two years and your young Isabelle will remember you and the promise you made her,"

Once the two years was up Agatha returned to the Institute knowing that the spell would have worn off and praying that Isabelle remembered the promise that she had made her. When she had returned she was greeted by a much taller Alec who glared at her before giving her a hug, showing that he always wore the and that she had give him but never knowing exactly what it stood for.

"You gave me this...so I wouldn't forget you," Alec whispered, Agatha looked closely at the band that she had given him back then and noticed something that wasn't on it originally.

"Magnus..."Agatha muttered she knew that her big brother had done something without her knowing but she hadn't known what until just that moment. "Nothing Alec, have you and my kid brother become parabatai?" She questioned, noticing a new mark on his arm.

"Yes, just recently...are you prepared to be Izzy's? And aren't you scared that if you do the spell again that it will break the bond?" Alec had so many questions that he had to ask her and so little time in which to do it.

"I am, and it's okay...I've been working a way around that – the things I gave you, a certain warlock did something to them without my knowledge," Agatha told him, before she motioned for him to get the bow and arrow. "Show me what you can do with that now?"

"You're on," Alec smirked grabbing the bow and arrow before the pair of them disappeared outside. "By warlock...you mean Magnus Bane don't you?" he questioned as they stopped walking and found a tree to fire at.

"Yes...and that's only because he's my big brother, just like Jace is my little brother," Agatha told him, as they both prepared to fire at the tree at the same time. "Have you been practising on aiming at something small?"

"Damn it, I knew you were the reason I did that whenever I fire," Alec laughed and nodded before he fired his first shot as Isabelle and Jace ran outside to them.

"Aggie! You're back, how long?" Isabelle questioned wrapping her arms around the older girl.

"Long enough for us to become parabatai's like I promised," Agatha replied returning the hug and grinning at her.

"Aggie, don't go again please," Jace said looking his older sister in the eyes as he spoke, a lot had changed in the two years that had passed.

"Jace, you know that I can't stay for long. I'm still getting the hang of things but I'm always here for you," Agatha told him, as she pried Isabelle's arms from around her. "Izzy, let go please,"

"If I have to," Isabelle was reluctant to let her go but did and almost as soon as she did Agatha had moved and wrapped her arms tightly around Jace and whispered in his ear that she was always a part of him no matter what happened.

Soon enough and Isabelle and Agatha's parabatai ritual had been performed and they would be linked for all time just like Jace and Alec. A short time after the ritual Agatha again gave Alec, Isabelle and Jace something that would always be with them, no matter what. Isabelle she gave a phone number, Alec another leather band with different words inscribed, and Jace a thin chain that could be easily hidden. This time she alone, or at least she thought that she was alone, managed to cast the spell that would erase her temporarily from their minds for roughly the next six years.