Summary: Clary had a twin. What if her twin was brought up the way she wasn't? As a shadowhunter. Drama ensues when Jace and Clary meet her. Post CoB

"Kat!" Katherine turned to see her best friend running up to her.

"What's up, Celina?" asked Kat. Katherine Morgenstern was a shadowhunter. She'd never met her father, but knew he was evil. It had been evident of that. She had been adopted by her mother's, Jocelyn Fairchild, friends, the Penhallows. When she was four years old, she met Celina and the two instantly became best friends and were parabati. Now she was sixteen and one of the best shadowhunters her age in Idris, the shadowhunter country.

"Cole said that we've been called out to New York's institute to work with the shadowhunters there. Some downworlder problem, I think," Celina said. Cole was Celina's brother.

"Have you seen Nix?" Kat asked Celina. Nix was Celina and Cole's third triplet.

"Nope," she said. "He disappeared last night and didn't come back. Wouldn't be the first time, though." They laughed. Nix was known to disappear for a night and come back in the morning hung over. Celina's parents stopped fighting Nix about it after the fourth or fifth time, they saw he was never going to change.

"So, when do we leave?" asked Kat nervously. As good of a shadowhunter she was, she hated killing things. She did not care wether it was a downworlder, demon, or anything else, she did not want to kill it, even though she did. When she was eight years old, she had been attacked by a ravener demon when traveling her adopted family. After that day, she swore to kill demons and downworlders if she had to.

"Ummm," Celina thought for a second before answering. "We have two or three hours. Your mom knows. I'm not sure if Aline is coming, though." Aline was the Penhallow's biological daughter. She was a good sister, even if she was insensitive at times. Kat had learned at a young age that if she wanted an opinion or advice, Aline was not the person to go to.

"Kay. You going to go pack?" asked Celina.

"Yeah, I just finished unpacking from Paris and now we're leaving again!" she groaned in mock exasperation.

Celina laughed, "True. At least this time we can speak English and not French. And, while were at it, can't English people speak English!" Celina said in mock horror, referring to their time in England when they could never understand what people were saying.

"Hey, Fauna," Kat greeted her tortoiseshell cat in front of her.

"Hey," Fauna greeted. As a favor from a warlock to Kat, he had made Fauna smarter than average cats and smarter. She could talk as well as a human, and could fight as well as a cat could. Fauna had been very helpful to Kat, Celina, Cole, and Nix when they were fighting demons. The warlock had also added a 'spell lock,' as he called it, so that Fauna would not be changed back into an average cat.

"What's up, Fauna? You look down," Celina asked as she scratched the cat behind the ears.

Fauna purred before answering, "You guys are leaving."

It took a moment for Celina and Kat to figure out what she meant. Then, "Oh!"

"We're going to take you with us!" Celina said.

"Yeah, Fauna, we wouldn't leave you behind. What makes you think that?" Kat thought for a moment before saying, "What did you break?"

Fauna purred a laugh, "I didn't break anything, but I doubt you'll need me with those three other shadowhunters helping."

Celina and Kat scoffed, "They could never replace you, Fauna. And, don't forget, we got called to help them. I doubt they'll be much help if they can't solve a small downworlder problem."

"I guess," Fauna was still skeptical. "Just don't forget to pack for me!"

Celina and Kat agreed as Fauna turned to go do whatever cat's did before they walked upstairs to Kat's room. When they reached it, Kat called, "We're back!"

They heard a pause in the clanging from the training room, which they took to mean they had been heard, before dragging Kat's duffel bag from the closet and throwing it onto the bed.

"What are you doing?" asked Kat as she saw Celina going through her mundane clothes.

"Well, we're going to New York. They have to have some good clubs there. Plus, you can't walk around New York all the time with your shadowhunter gear on, people will wonder what the heck is wrong with you. Plus, I don't want to be walking around in mundie clothes while you stay in all black," Celina reasoned.

Kat sighed before choosing her favorite clubbing outfits and adding them to her duffel. After putting all her mundane clothes in, she added half her closet of shadowhunter gear. Celina threw in a few pairs of shoes. When Kat raised an eyebrow at her, Celina just shrugged and threw three or four more in.

Then they moved onto jewelry. Kat and Celina always gave each other, as tradition, a piece of jewelry with a mark on it. Both girls preferred necklaces, bracelets, and rings, to other pieces of jewelry. They each had a few pairs of earrings and a few anklets, but did not like them as much.

"Don't forget your bracelet," Celina shrieked.

Kat turned to Celina and held up her right wrist. Celina sighed in relief. It was a Juicy Couture butterfly cuff bracelet Celina had bought for Kat during their birthday in California. That was another things that brought the girls closer, they shared a birthday. Kat had bought Celina the same bracelet in silver and the girls brought them everywhere. With extreme skill, they had managed some small runes on the back of the bracelet.

"You got yours?" asked Kat. Celina nodded and held up her left wrist.

"Great, I think that's all," Celina said as she peered into the duffel.

"Umm, I think you're forgetting a very important thing," Kat tried to point out to her friend.

"What's that?" asked Celina in confusion.

"Weapons?"

"Oh! Yeah, I forgot. Let's go down. Then we'll head to my place for dinner and packing. You just know that Cole and Nix aren't packed. They are boys, after all," Celina giggled.

"Yeah, let's get going," Kat agreed.

"Okay!"

"Wait!" Kat said.

"What?" asked Celina in annoyance.

"We forgot to pack for Fauna! She's coming with us!"

Both girls ran back to Kat's room and found Celina sitting beside her considerably smaller duffel angrily.

"Sorry, we forgot!" both girls said at the same time. Fauna just shook her head in annoyance before walking out. Kat walked over to the mini fridge in her room. Technically, it did not work in Idris, but there was a freezing rune on it that kept there food cold. She grabbed a few cans of cat food that would hold them off until they bought more in New York. She also packed a bottle of water, both of Fauna's water dishes, and some treats.

"Wait," Celina said. "Don't forget her sweater. It is December, it could be snowing."

"Could be? Of course it is," Kat said. Before they went to get weapons, they grabbed a few of Fauna's collar's with runes and Fauna's anklets.

"Happy?" asked Kat in mock annoyance as they passed Fauna. All they heard was Fauna's retreating laugh.

They entered the weapon's room. Inside were rows of seraph blades and shelves of steles. Many other weapons that both girls knew every name to. They grabbed three seraph blades for Kat and an extra stele in case, Celina had her own weapons at her place.

"Let's go to my house so I can pack," Celina said.

"Kay. If we've got extra time, could we practice? I haven't practiced with you in ages," Kat asked her friend with pleading eyes.

Celina laughed, "Of course, you're my best friend."

"Hey, Fauna, you better get your furry tail down here or else you aren't coming!" All they saw was a blur of brown and tan streak down the stairs and out the door in the direction of Celina's house.

She paused and looked back, "You two coming, or what?"

The friends laughed and followed Fauna as she glared at them with her icy gray eyes. "If I didn't know better," she stated. "I'd say you're mundie's. But you're not, so hurry it up!" They saw her run around the corner onto Celina's street before laughing.

A/N: Love it? Hate? Review please! : ) (Constructive criticism accepted)