City of Heavenly Fire

Sebastian hits the Institutes with Shadowhunters twisted by the Infernal Cup and, in Los Angeles, takes Mark Blackthorn. Jordan Kyle dies. In Alicante, Clary claims Heosphoros, the Morgenstern sword. The Seelie Queen, now Sebastian's ally, lures the Downworlder representatives to Edom, the demon realm, and Clary, Jace, Simon, Isabelle and Alec follow. Clary pretends to accept ruling beside Sebastian and stabs him with Heosphoros. For a moment he becomes Jonathan again, destroys the Infernal Cup and dies. To get out of Edom, Simon gives Asmodeus his immortality and his memories of the Shadow World. Months later, Jocelyn and Luke get married.

1. ChangeWho loses their memories

   In the book, Simon gives Asmodeus his immortality and his memories of the Shadow World to get the group out of Edom. On the show, Clary is the one who loses her runes and memories.

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2. ChangeLab-made heavenly fire

   In the book, the heavenly fire has been inside Jace since the previous volume. On the show, it comes from Aldertree's secret project to turn Downworlders mundane, and it ends up in Isabelle.

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3. ChangeA different wedding at the end

   The book ends months later with Jocelyn and Luke's wedding. On the show, the finale wedding is Alec and Magnus's.

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