The hunt is on for Jace Wayland, and Alec and Isabelle hope to reach him before the rest of the Shadowhunters do. With orders from the Clave of "shoot to kill," the Lightwood siblings must act fast. Also on his own search, Simon turns to Magnus for help when he finds himself at odds with both Raphael and Aldertree. Meanwhile, Clary struggles to find where she belongs since she doesn't seem to fit into the Shadowhunter world, yet can't go back to her mundane life.

Clary continues to struggle with the new Shadowhunter order as Jace is being held in The City of Bones with an unknown fate, and all suspicion in the Shadowhunter world continues to rest on Valentine's daughter. When duty calls, Clary gets a little reprieve from the family drama as she helps Alec and Isabelle hunt down a powerful demon. But what starts out as a routine mission quickly puts the Institute on high alert, and what happens next will change everything for the Shadowhunters and their Downworlder friends.