The Mortal Instruments is a series of six young adult fantasy novels written by Cassandra Clare, the last of which was published May 27, 2014. The Mortal Instruments is chronologically the third series of a proposed five in The Shadowhunter Chronicles but it was the first one published. The book series has become one of the most popular within the young adult genre of paranormal romance/urban fantasy, but Clare did not originally intend to write the series for teens. When she began writing City of Bones, she did not view it as a young adult work, but first and foremost as a fantasy novel, where the main characters just happened to be teenagers. When she was approached by a publisher interested in aging up her characters, she ultimately decided that she "wanted to tell a story about characters at that crucial life stage just between adolescence and adulthood, where your choices determine the kind of person you're going to be rather than reflecting who you already are."
The books are set in Brooklyn, New York. Clary Fray is just your ordinary, red haired, teenage girl, who dreams of being an artist. She has a best friend, Simon, and they are inseparable. One night, when Clary is about to go out with Simon, her mother is acting weird. When Clary gets back, her mother is gone. Clary adjourns on a treacherous journey, after finding out she's not just an ordinary teenage girl after all. She's a Shadowhunter. A breed of humans with angel blood, who fight demons while the rest of the world has no idea that the demons nor the Shadowhunters exist.