*Spoilers for Clockwork Princess

I don´t know where in the timeline this is but it´s after Clockwork princess but before Jem stops being Brother Zachariah.

"Aaah!" Alec screamed in his sleep. He had been bitten by a demon in a fight and had been unconscious since then. For some reason no rune was working on him. Jace who had been walking in circles for about thirty minutes stopped when he heard the scream and went to sit with Alec. Brother Zachariah stod on the other side of Alec.

"Why isn't he getting better? Do something!" Jace yelled at Brother Zachariah.

I am trying, but nothing is working. I've tried everything the brotherhood has taught me. I am truly sorry. Brother Zachariah said in Jaces head.

"But you must do more, you have to help him! He's my parabatai" Jace pleaded.

As I said. I really am sorry. I know what it's like to lose a parapatai.

"You had a parabatai?" Jace had forgotten that shadowhunters can become Silent brothers. "How did it feel like when he died?" Jace immediately regretted that he had asked but Brother Zachariah answered:

It is probably the worst feeling in the world...

"Yeah, tell me about it." A voice suddenly said. Both Jace and Zachariah turned their heads towords the voice. Their was a man standing near the wall. He didn't look older than 25 years old. He wore clothes that looked like they were from the twentieth centruy and had dark hair and very blue eyes. Brother Zackariah just stared at the man like he couldn't belive what he was seeing.

"Who the hell are you?" Jace asked angrily. He was not in the mood to talk to some strange cosplayer.

"I don't think you should talk like that to your ancestor. It's actually quite rude" The man said. Jace could hear that he was brittish.

"Who the hell are you?" Jace demended.

"I'm-"

"Will. Will is that you?" Brother Zachariah suddenly said. It was the first time he hade opened his mouth in years.

"Wait, since when can you talk? How-

"Yes, it's me James." Will said ignoring Jace.

"How are you here?" Brother Zachariah said. He was still sure he was dreaming.

"Raziel sent me down here to complete my mission" Will said.

"Raziel? The angel? Have you been in heaven-

Jace was very confused and wanted to know what was going on and why this man kept calling Zachariah James.

Will and James was still staring at each other and completly ignoring Jace.

"What mission?" James asked.

"To save my great-grandsons parabatai of course! Even if he is a Lightworm…" Will answered.

Now it was Jace's tur to stand shocked in silent. This man couldn't be his great-grandfather right? But their was no one else in the room who had a dying parabatai…

"Are you here to help Alec?" Jace asked.

This time Will did not ignore him.

"Yes I am." He said and walked towards Alec. He took out something from his pocket that looked like a little bottle with green liquid inside. Before Jace could ask what it was Will had poured the liquid into Alecs mouth.

"Can someone tell me what's going on here? Who are you and why do you keep calling Brother Zachariah James?" Jace asked.

"Maybe i should re-introduce myself. I am William Herondale, your great-grandfather. I died in 1937 but came back to earth to save your parabatai. And the reason why I keep calling him James is simply because that is his name." Will said.

"How do you know?" Jace asked.

"Well, I have known him since I was twelve years old and he's my parabatai and like a brother to me. It would be quite weird if I didn't know what his name was. Wouldn't?" Will said.

At this, James seemed to have snapped out of his shock and he was now walking- no running towards Will. When he reached Will he pulled him into a tight hug and Will immidietly hugged his parabatai back. They stood like that for what seemed like hours and when they finally seperated James said: "I have missed you so much, brother" Will smiled and answered: "I have missed you too, Jem".

"Um, I'm sorry to interupt but Alec is nose bleeding." Jace suddenly said. He had been watching the reunion from next to Alec.

"It's okay that's normal when you take the medicine I gave him." Will said.

"Oh, okay. Hey, why do you look so young? Shouldn't you be an old man?" Jace said.

"When you come to heaven you get to choose how old you are going to look. I chose when I was 23 because thats when my looks were at it's finest but Let me tell, I was a very good looking sixty year old." Will said proudly.

"Why do I look so different from you? Are you sure that you're not Alec's ancestor?" Jace asked.

"Don´t you think i would know if I had married a Lightworm?" Will said.

"Why do you call them Lightworm?" Jace asked.

But before Will could start his rant Jem said:

"You two are actually very alike. Maby not in apperance but in the way you talk. And also you're both afraid of ducks."

"Is it from you I have gotten my hatred of ducks?" Jace asked.

"Good. At least my most importent rule has gone through genarations: Never trust a duck" Will said proudly.

Suddenly the door opened and Magnus Bane ran towards Alec's bed.

"I came as soon as could! How is he?" Magnus asked and you could hear that he was very worried. He didn't even notice Will or Jem as he ran inside the room.

"He is going to be okay. We gave him a special delivered medicine." Jace said and Magnus didn't even react at the "special delivery" part.

"Okay good. I was meeting an old friend I haven't met in years when I found out about Alec and I couldn't just leave her so i brought her with me. She insisted on waiting outside but if Alec is going to be okay I might as well bring her in here. I think you should meet her Jace." He said still not noticing Will and Jem. "You can come in. It's okay!" he screamed.

It was quite for a few seconds but then the door opened and a girl walked in. She wore a pair of jeans and a purple T-shirt. Her brown hair was in a high ponytale.

"Let me introduce you to-" Magnus began.

"Tessa" Will said from were he was standing next to Jem. Magnus and Tessa turned and looked at them both of them gaped.

"Will" Both Tessa and Magnus said at the same time.

Tessa felt like she had gone back in time to when the two boys never left the each others side. Will looked young again and Jem had taken of his hood so you could see his face. Though his face was scared and had runes you could clearly see that he was Jem. She had seen Jem a few months ago on Blackfriards bridge but she was still happy too see him again so soon. But of course when she started running it was towards Will, her husband she hadn't seen in over seventy years.

They hugged for at least five minutes and when they let go they had both said "I have missed you" atleast 10 times each and both of them were crying. Then Tessa hugged Jem just as tightly and Will went to hug Magnus. When they all was done hugging Jace said:

"So… How do you guys know each other?"

For two hours they all sat and explained how they knew each other and about their adventures, they talked about Clockwork creatures, curses, yin fen, and proposals.

Jace was fascinated and he actually felt proud to be called a Herondale.

"I only have five minutes left here before I have to go back to heaven." Will said.

"Do you think you ever will be able to come back?" Tessa asked.

"Well now that I know that it's possible I'm definitely going to use it against Raziel." Will said with a smug expression.

"Just don't make him too irritated" Jem said.

"I'm already dead so what can he really do?" Will said.

"Take you to hell" Jace said earning glares from Jem, Tessa and Magnus.

Everyone said their goodbyes and hugged Will one last time.

"Farwell for now but not forever" Will promised and then he disappeared.

A few hours later when Tessa and Jem also had left Alec suddenly started to wake up.

"What happened while i was unconcious?" Alec asked.

"Nothing special. I just met my great-grandfather and great-grandmother and found out Brother Zachariahs real name." Jace said.

"You did not." Alec answered.

"Yes I did. And guess how you got cured. Raziel made a medicine for you and gave it to my great-grandfather so he could give it to you." Jace said.

"You're lying." Alec said.

"No i'm not! Just ask Magnus. He has even kissed my great-grandfather but that was like 100 years ago!" Jace said.

"You have kissed who? "Alec said looking at his boyfriend.

"This is going to be a long day…" Magnus muttered then he leaned forward and kissed Alec's cheek.