Clarissa Fray didn’t know anything about the existence of demons and other supernatural beings, until she met Jace Wayland, Isabel and Alec Lightwood. A day after meeting them, her mother disappeared or was kidnapped because when she came home, she was attacked by a demon and ended up being saved by Jace and later on was talking to Madamme Dorothea. Using the portal in Dorothea’s apartment, they were directly sent to Luke’s (her mother’s friend) house where they also found Simon, her bestfriend, spying.
After she discovered things about Luke, they went back to the institute, together with Simon. Later on she discovered that her mother was a shadowhunter, a part of the circle which is under the role of Valentine. She also discovered that her memories have been blocked by Magnus Bane, who was ordered by her mother, Jocelyn, so she’d stay out of the otherworld. She then discovered that Jocelyn was also Valentine’s wife.
At that time, they were looking for a cup because they have to get it before Valentine could. Clary discovered where the cup is, which her mother hid on Dorothea’s tarot cards. When they had the cup, they were betrayed by their tutor, Hodge who gave the cup to Valentine and Clary ended up at the company of Luke and she discovered a few more things like: Luke is a werewolf; his name is Lucian; he was once Valentine’s friend; he ran away with Jocelyn; her father is really Valentine and that she has a brother named Jonathan, who died. As the leader of the wolf pack, they decided to attack Valentine to save Jace and her mother. When they reached his place, they saw her mother lying and chained, she also saw Jace, but a different Jace, different from the guy she fell in love with. When she met Valentine, he called Jace as “Jonathan” and told them that they are siblings.
After the fight, Valentine was transported, Simon and Clay became even closer, Clary’s mother is still in comma and Clary and Jace’s relationship as siblings turned out to be okay.