This Means War

After the war with Valentine, Clary, Jace, Isabelle, and Simon get sent into the mundane world of high school. The four are forced to enroll in Clary and Simon's old school ,Goode High, where they meet a certain green eye boy. Although he seems friendly enough, Jace can't shake the feeling he gets around him. Who is this boy? and why does he seem so powerful?