Through this together | Alec Lightwood
Shadow Hunters are people that are half angel half mundane (human). They protect the human word from the demon world, downworlders.
Kayla Wayland is Jace Wayland's younger sister. They grew up and was raised together with Alec and Isabelle Lightwood. Their parents took Kayla and Jace in like their own. They trained together, go on missions together, and did everything together. Kayla and Isabelle are parabatai, like Jace and Alec is. The four was best friends had a inseparable bond.
Just like Jace was close to Alec, so was Kayla. Her and Alec was very close. She was the one person he opened up to, and showed a different side of him. As they grew older Kayla grew feelings for Alec, as did Alec. Soon they started dating and have been since.
The four shadow hunters' daily life was the same, they went on a missions and killed demons. That was until Clary Fray came along.
What will happen once she comes along and finds out that she is a shadow hunter herself like her mother and learns about the shadow world. What will happen when they find out Valentine is still alive and has Jocelyn Fray; Clary's mother.
They and The Clave will do anything to get their hands on the Mortal Cup; the most important thing in the shadow world. Before downworlders do, better yet before Valentine does. Everyone wants The Mortal Cup and it's up to the shadow hunters and Clary to find it.
Secrets will be unraveled and trust will be broken.