CASS

"Are you going to get that?"

Cassandra Herondale glanced up from her deep perusal of her mother's rune book to stare blankly at her little brother. "Get what?"

Casey Herondale was a long and lean figure hovering at her door. He jerked his blond head towards the stairs. "Someone's at the door."

Cass dismissed him with a sweep of her curly blond locks back to the book. "You get it."

"You're the eldest. Mom and Dad always say you should get the door when they're not home." Casey returned petulantly, not so easily dismissed.

With a roll of her glassy green eyes, Cass rose from her comfortable perch on her window seat and flounced past her brother, curls bouncing. She made her way down the ornately-railed staircase that centered their Manhattan townhouse to the front door. She peered through the peephole, blinked twice in quick succession, and opened the mahogany door for the total stranger standing on her doorstep.

Staring up at her, stony-faced, was a waifish girl with midnight-black hair framing a pallid face and fiery golden eyes. Wearing all black leather, including a leather jacket in the sweltering summer heat, Cass could already tell she would be a force to be reckoned with.

"Who are you?" Cass asked, guardedly, after her once-over.

The waif girl tapped her right boot on the ground impatiently. "I'm Morgan Beckford, and my mother kicked me out. My father is Jace Herondale, and I need to see him."

Cass instantly burst out laughing. It was ludicrous to even entertain the idea that her father had fathered a long lost sibling. What did she want? Blackmail? A chance to claim the best fighter the Shadowhunter world had ever laid eyes upon? Money?

"I think you picked the wrong Shadowhunter family to play with, little girl," She moved to shut the door, but was abruptly cut off by a foot in the doorway. Surprised, she let go of the door knob and swayed out of the way as the door was flung open again.

Morgan Beckford stormed into the Herondale house, eyes blazing. "Would you just listen to me?" She demanded irately.

Silently, Cass closed the door behind her. With a roll of her eyes, she said, "Fine. This better be good." She flipped her cascade of golden curls over her shoulder imperiously and led Morgan into the family room. "Have a seat."

But Morgan didn't want to sit down. She baltered around the room, dancing artlessly with no particular grace or skill, but with great enjoyment. Cass was no majime. She wasn't an earnest or reliable person who could simply get things done without causing drama.

"What are you doing?"

Morgan ignored her, flitting to the mantelpieces displaying their family photos. Cass watched Morgan gaze at one in particular: the one in which her father, Jace Herondale, was wielding his seraph blade menacingly at imaginary demons. She remembered when that photo had been taken.

Her father had taken her and Casey to the park for shadow hunter training while her mother tagged along. Cass hadn't paying much attention to the intricacies of demon fighting because it bored her and goofed off as she usually did when she was forced to train. How tedious it was to do the same graceless motions incessantly without a hint of ebullience! To remain focused on the slightest movements without the slightest buoyancy! Yet Jace was jovial and jaunty as ever, like obliterating demons was such a fun pastime.

Casey was a reluctant learner as well, but he was quick to absorb information and lightning on his feet. He found no particular revelry in fighting, but he couldn't help being so innately gifted at the art of shadow hunting. He sparred with their father effortlessly.

It was when Jace took it upon himself to simulate a demon attack, twirling his blade and slicing at the wind, Clary pulled out her camera to capture the moment and save it forever. And so it was that her father's knotted eyebrows and fiery glare was sealed forever on their mantelpiece.

"Nice, huh?"

Both girls turned around at the sound of Casey's voice from the doorway. He ambled into the room and folded his long limbs into an armchair. He waved for them to sit down. After a slight hesitation, Morgan steeled herself onto a plush couch. Cass followed her to perch on the opposite end. She could see dagger glinting underneath the cover of the girl's leather jacket.

"I mean, you're obviously Jace's daughter," she began, "with those flaming eyes. I just don't get how we never knew about you? Like, that you existed?"

"I didn't know who my father even was until recently." Morgan fired back, glowering at her. "My mother would never tell me about him. I begged and begged her to give me any little detail but she adamantly refused. I hated being kept in the dark."

Casey was staring at her intently, as if he could etch a portrait of her as a member of the incandescent Herondale family just by memorizing her face. Cass could tell he was intrigued; fascinated, even. "So how did you find out about Dad-us?"

Morgan sat up cross-legged and held her knees. She'd almost look like a frightened, frail child if it weren't for her hard-edged mouth. She opened it to retort, "I didn't. You – your whole world – found me."