Main Characters: Clary, Jace, Simon, Alec, Magnus, Isabelle, Luke, Mia, Jordan, Jocelyn, Sebastian, and all the others we’ve seen so far.
New Characters: There aren’t really any new characters that we see in any way more than just in passing. We do get some references to Will and Tessa from the Infernal Devices series. And we may see a little more of some of the folks referenced in passing, but since they are merely mentioned in passing, let’s wait to see if they show up in the next book.
Main Premise: We pick up where we left off, Jace and Sebastian are connected as a result of Sebastian’s ceremony with Lilith. Jace and Sebastian are missing and Clary is beside herself. Jace, with Sebastian in tow, to convince Clary to go with them. And Sebastian stabs Luke with a dagger that has some sort of demon metal in it so he isn’t healing right. Clay goes to see the Seelie Queen to get some help, and she is warned that if she finds Jace, she might not find him the same. She hatches a plan to go after him since the Clave has suspended the concentrated search for him. She ends up infiltrating the Jace/Seb duo, only to be taken to Sebastian’s dimension traveling apartment. She can speak with Simon telepathically through the fairie rings she steals for the Seelie Queen. Meanwhile, first Izzy and Jocelyn travel to the Iron Sisters to find out how to save Jace and see if they can make a weapon that will hurt only Sebastian or sever the connection. They discover that only a heavenly weapon will do it. Then, Simon, Alec, Izzy and Magnus try to figure out a way to save Jace and they do this by first summoning a demon, and then having Simon summon an angel (since with the Mark of Cain, the angel can’t kill him). The angel gives Simon Michael’s sword, but removes the Mark of Cain. Sebastian is controlling Jace, and steals the fairie ring from Clary. When it’s time to execute Sebastian’s plan, Clary gets the info she needs to know that Simon has the sword, she tells Simon and everyone where to go and when, and then she crushes the ring since it turns out that Sebastian is in contact with the Seelie Queen and she is on Sebastian’s side. The battle ensues, he manages to create a bunch of demonic Shadowhunters.
But, Clary stabs Jace since she can’t get to Sebastian. The sword burns off all the evil in Jace and he survives. But, he also still has some piece of heaven in him, so he sort of glows and burns. But he survives. And, Sebastian gets away.
Other Important Things to Remember for Later: Magnus and Alec break up. Maureen kills Camille. Mia and Jordan are a couple. No one knows the implications of Jace having something heavenly inside are, not even the silent brothers. Sebastian has a “fake” mortal cup. He resurrected Lilith, but it seems that she still isn’t really present either. Most of the dark shadow hunters have been captured or killed. The clave got an excuse as to why they weren’t told what was going on. Izzy and Alec’s dad is coming back to NY. And Clary thinks that she and Jace are sort of the prize for Sebastian – that he won’t try anything until he has a plan all lined up. He wanted it to look like the three of them were all on the same side. Brother Zachariah might be someone we know or will meet in the Infernal Devices. And Clary tells Izzy to tell Simon how she feels since they sort of get together but it seems Izzy thinks Simon might not be interested.