A/N: So this is based on a headcanon my friend and I made up. The headcanon is this *ahem*:
Jace has just arrived at the Institute and is getting pretty friendly with Alec and Isabelle. But, Alec notices that he like Jace as more than just a friend or battle partner. So, yeah, yeah, ya'll already know this. But the headcanon my friend and I made up is that we think that Jace would totally lead Alec on. So, basically this story is just Alec being salty and denying his gay-ness, Jace being flirtatious, Max being a young little thing, and Isabelle being hella annoyed.
Note: I do not own The mortal Instruments
Alec pulled the covers on his bed. He liked making his bed every morning. It gave him a sense of order and calm.
Then Isabelle came bursting into the room destroying all the calm in a fifty mile radius. She surveyed the perfect mix of neatness and chaos that was her brother's bedroom. Blue walls, covered in pictures of the family and horribly scribbled drawings of runes and demons. A rickety wooden desk, small bed, and black night table were the only pieces of furniture. His closet door was painted pale yellow, with one large poster of the only mundane band Alec liked, Coldplay. Another green painted door led to Alec's bathroom, which was boring and painted in shades of grey, white, and gold.
"How do you keep your room so tidy?" She asked, confused because her room is so messy you can't even see the floor.
Alec just shrugged. That's pretty much how he answers every question. "So why did you come rushing into my room like that?" He asked.
"Oh, Mom told me to get you. We have a visitor. Whoever they are sounded important." She replied. She had moved from the doorway and was now fiddling with stuff on his desk.
"How important?" Alec asked, moving away from the bed. Worries running through his mind. Was there an attack? Is dad back from his trip? Was he in trouble?
"So important that she left a council fire message for it." Isabelle responded. Alec flinched slightly at the news. That important huh?
The two kids left room and walked the long halls towards their parents office where Isabelle said their mom was. The Institute had these beautiful windows made with really well designed stained glass. The light reflected on the bright colors; blue, yellow, green, red.
Alec liked to count all the different patterns but so far he's only gotten up to 36. After the 15th pattern they arrived at the large office door.
Isabelle pushed the door open and walked in with Alec trailing after her. Sitting at the desk was their mom, Mayrse. She was the leader of the New York Institute for now while their father was on a business trip to Idris.
There was someone else at the desk too. A small boy about their age (11) with the blondest hair Alec has ever seen was standing next to their mother. They seemed to be in deep conversation.
But the moment Mayrse noticed the pair she stopped talking. "Alec, Isabelle. This is Jonathan." She said, gesturing to the blond boy.
"Its Jace" He mumbled.
"What was that?" Mayrse asked. "You'll need to speak a little louder Jonathan"
"It's Jace" He repeated. "You keep calling me Jonathan and that's not my name."
"Hi Jace!" Isabelle exclaimed, deciding she has been far to silent. "I'm Isabelle but you can call me Izzy."
"And that's my brother Alec." She continued pointing at Alec. Alec gave a halfhearted smile while Jace just gave a small wave in response.
"Isabelle stop bombarding the boy." Mayrse scolded. "Jace is going to be staying with us until further notice, so treat him well, Okay?"
The two Lightwood kids nodded. "Now Isabelle, go show him his room. It's across the hall from Alec's."
Isabelle grabbed Jace's arm and led him out of the room. Alec was starting to follow but his mother stopped him.
"Alec, do me a favor and help Hodge in the training room." She asked. He nodded and walked off.
Alec's job was to clean the weapons but he didn't think he did it properly. He was to busy thinking about the Jace Wayland, his new brother and how he felt about this situation.