Cassandra Clare’s six-novel YA fantasy series The Mortal Instruments is being developed as a possible movie franchise, TheWrap is reporting.

The books tell the story of a teen girl who becomes involved with the Shadowhunters, a group of demon-hunters invisible to humans.

The first movie, to be called The Mortal Instruments, is based on the first book in the series, City of Bones, and is tentatively scheduled for a 2012 release. Further movies in the series would follow should the first one prove successful.