Clary Fray finds out on her 18th birthday that she is not who she thinks she is, but rather comes from a long line of Shadowhunters--human-angel hybrids who hunt down demons.

Jace suspects that Clary's memories are the key to locating Jocelyn and the Mortal Cup; Jace, Isabelle and Alec take Clary to face the Silent Brothers in the City of Bones; Simon attempts to adjust to his best friend's new life.

Clary, Jace, Alec and Isabelle work to rescue Simon from the vampire hideout, Hotel du Mort.

After getting a clue about who may have wiped Clary's memories, the crew hunts down the High Warlock of Brooklyn, Magnus Bane. With all the warlocks in hiding from Valentine, the team lures Magnus out with an offer he can't refuse--a killer party and something very valuable.

Tensions escalate between Alec and Clary when they don't see eye to eye on the best way to hunt down Valentine; Alec is put in charge of keeping Clary safe when Jace and Isabelle are sent on a mission; the New York City Werewolf pack begins their hunt for Clary and The Mortal Cup.

With Luke in dire need of help, Jace, Clary and Simon take him to Magnus' lair in hopes of saving his life. Once there, the story of how Valentine came to be evil, and Jocelyn and Luke's past is revealed to Clary in hopes of triggering her memory of what happened to The Mortal Cup.