"The Mortal Instruments: City of Bones" is a young adult fantasy novel by Cassandra Clare. It follows the story of a teenage girl named Clary Fray, who discovers that she is part of a hidden world filled with Shadowhunters, demon hunters who protect humans from supernatural threats. After her mother goes missing, Clary learns about her family's connection to this secret society. As Clary navigates this new reality, she meets Jace Wayland, a skilled Shadowhunter, and other characters like Simon Lewis and Isabelle Lightwood. Together, they embark on a quest to find Clary's mother and uncover the truth about her own identity, facing various challenges along the way.