City of Bones by Cassandra Clare

Clary Fray goes to a hot club, and witnesses a murder! Except, she is the only one that can see it happening, and the body disappeared into thin air. They introduce themselves as Shadow Hunters: a secret world of warriors dedicated to destroying demons. The next day Clary’s mother goes missing, and Clary is almost killed by a demon! Why is this happening now?... --Shay G., student