It is the second novel in The Infernal Devices trilogy and is written through the perspective of the protagonist, Tessa Gray, who lives at the London Institute among Shadowhunters, a group of half-angel/half-human beings called Nephilim.

The book also contains many quotes referring to famous pieces of Victorian literature, for example, Alfred Tennyson's The Palace of Art, Charles Dickens' A Tale of Two Cities, and the works of Samuel Taylor Coleridge.

[1] After the events of the previous book, Charlotte Branwell, accompanied by her husband Henry, Tessa Gray, Will Herondale, Jem Carstairs, and Jessamine Lovelace, are called to a Shadowhunters' Council meeting to give testimony regarding her failure to capture Axel Mortmain, the leader of the Pandemonium Club.

The Institute begins searching for Mortmain and discovers that the Clave killed his adoptive warlock father, John Shade, the creator of the automatons, and mother, Anne, before the Accords were signed.

Upon returning to London empty-handed, Will confesses to Magnus Bane that he ran away from home and emotionally shut himself off from everyone to escape a curse caused by a demon he unwittingly released from his father's Pyxis box.

Upon getting a negative response from Woolsey Scott, head of London's werewolf pack, Charlotte suspects that Mortmain hired rogue werewolves to work on his automatons.

Gideon becomes close with Sophie throughout their training and reveals to Tessa the reason why Benedict hates the Fairchilds: his uncle Silas committed suicide after his forbidden relationship with his parabatai was outed by Granville, leading his mother, Barbara, to die of despair.