a/n: For those who need a refresher on COB: This is a flashback. Set right after the gang leaves Magnus' party and Jace and Clary run off without explanation to go find rat-Simon, who has been taken by the bloodsuckers.

-FLASHBACK-

"Isabelle, I think they're gone," Alec turned around, running a short distance the way they had come. "They are... they're GONE!" Alec shouted back to his sister, who looked utterly unconcerned.

"Calm down Alec—I'm sure they just fell behind for some privacy… Not that big a surprise considering the way Jace has been eying Clar-" She caught herself mid-sentence and looked up at Alec guiltily. She took a couple steps towards him before she noticed how determined Alec looked to ignore her remorse.

"That's not the point right now." He responded quickly.

"I'm sorry Alec, I just—"

"Why are you apologizing? Can we just focus on the situation at hand? 15 minutes ago Jace and Clary were trailing behind us, whe—"

"And Simon."

"What?"

"Jace, Clary, and Simon were behind us."

"Right. So sorry. How could I forget the foolish mundie who drank a fairie concoction and got himself turned into a rat?" His tone was drenched in sarcasm as he tried to bring the conversation back to the point. He was trying to be patient with her since he wasn't entirely sure she had completely sobered up yet.

"It wasn't his fault. I really should have…."

"OKAY. ENOUGH ABOUT THE MUNDANE. NO ONE CARES ABOUT THE MUNDANE," His reservoirs of patience were officially dry. "Jace is gone. He made up some excuse and ran off with only an untrained, unprepared, poor excuse for a shadowhunter whose suffering from magical amnesia and you're precious freaking RAT!." Alec was gasping now, unaccustomed to loosing his cool and raising his voice.

Isabelle stared at Alec, shocked by the outburst. She knew it was triggered by concern but it really wasn't like him.

"Seriously, Alec, I'm sure they're just around the corner or something. Don't worry so much." Isabelle laid her hand on his shoulder, hoping to comfort him a little.

"How could I not worry? In the past 2 days that girl has put Jace's life at risk so many times that I've already lost count! And he just keeps following her around like a blind man." Isabelle tightened her grip on his shoulder, trying to get through to him.

"Oh, and she's to blame for that? Come on, you know how Jace is…"

"I don't care about whose fault it is!" He turned as if to walk away, "What I care about is-"

Isabelle kept her grip on him, forcing him to look back at her. They locked eyes. "I know what it is you care about, Alec." She said it with such conviction that Alec was tempted not to argue. But he couldn't waste his time here going back and forth with her. He took a deep breath, calming himself before responding evenly.

"Well, if you know… then let me go Isabelle."

Isabelle paused for a second, searching his eyes, before reluctantly loosening her grip and letting her hand fall to her side.

"Just be careful okay?"

He turned his back to her and began walking swiftly away before mumbling over his shoulder, "When am I ever not careful?"

a/n: Next up- long awaited Magnus and Alec goodness! And for those who are curious, it will be a continuation of the current flashback.