"When my sister Clary and I turned 18, we discovered the truth about the world. Nothing that we thought was. No one was who we thought it was. And some people have a dark side. Really dark. We also discovered that whatever your destiny is... it will find you. And when it does...be ready." Cassie's life was so mundane that she didn't expect it to change so quickly. On hers and her sister 18th birthday, they discovered a completely new world. The Shadowhunters world. When their mother, Jocelyn, is kidnapped Clary and Cassie, with Simon, join the Shadowhunter Jace Wayland, and the brothers Alec and Isabelle Lightwood, to find her. Cassie wasn't ready to face demons, vampires, werewolves, warlocks and the unexpected love for the oldest Lightwood. [Shadowhunters season 1]