With word of Alec, Jace and Isabelle's activities with Clary reaching The Clave, a convoy is sent to observe the Lightwoods running the New York Institute. Once The Clave representative arrives, it is clear how much trouble the Lightwoods are in.
The Institute and The Clave go on high alert.
Meliorn reveals that Clary can locate Valentine by accessing a portal via an alternate dimension.
After receiving important intel about Valentine from a surprising ally, Clary, Jace, and Luke devise a plan to rescue Jocelyn and to put a stop to Valentine once and for all.
Everyone at The Institute prepares for the wedding of Alec and Lydia. During what should be a time of great celebration for many is far from it as they examine their relationships. Alec's parabatai should be at his side for the event, yet he and Jace are still at odds.