The demon recognizes James, who falls into the shadow realm (a unique power as a result of his warlock heritage) for the first time in 3 years.

Meanwhile, Cordelia Carstairs enters the London society along with her brother Alastair and mother Sona.

Her father has been arrested for supposedly mishandling a vampire raid, and the Carstairs wish to make powerful allies in London to save their reputation.

Lucie sees the mysterious boy from her childhood, who reveals himself to be the ghost of Jesse Blackthorn, the late son of Tatiana.

His mother asked Downworlders to preserve his body, so his spirit has remained trapped in the in-between.

James is swept into the Shadow Realm and sees a partygoer being attacked seconds before she collapses in the real world.

A demon attack wounds Ariadne Bridgestock and Barbara Lightwood, Thomas's oldest sister.

Later on, Grace requested him to use his shadow abilities to retrieve her Cartwright familial bracelet which Tatiana seized.

Cordelia, Matthew and Anna Lightwood (Christopher's older sister) visit Malcolm Fade and Hypatia Vex, where they inquire about the attacks and if the downworlders might have heard of it.

Ragnor visits the teenagers-sans Cordelia and Alastair, and gives them a lead - Emmanuel Gast, who he thought might be able to dredge up information.

He’s actually already been questioned with the Mortal Sword, which Cordelia was sure would clear his name as it requires the holder to speak only truth.

Christopher arrives with the results and the group discovers that the shards of wood were pieces of a Pyxis.

The next evening, James, Cordelia and Matthew accompany Anna to Hell Ruelle, where Hypatia is hosting a party.

This shocked the entire Enclave as demon poison had never been contagious before, and London is placed immediately under quarantine.

Matthew pushes the couple away and they hide in The Whispering Room, where James and Cordelia kiss passionately.

The next morning the Merry Thieves, Lucie, and Cordelia take advantage of the fact that Will and Tessa are gone for day-patrols, an added precaution by the Clave, and empty the Pyxis by letting out a Palpis demon named Agliarept, so that they may use it to trap the Mandikhor.

They explain to him, their plans of ridding the shadow world of the demon and Cordelia implores Magnus to help them by casting an illusion over Tower Bridge, to protect and distract the mundanes.

Cordelia stated that she wanted to be a merciful hero and Alastair merely said that the sword belonged to him as he was the Carstairs heir.

The group goes to Tower Bridge to try to fight and capture the demon, but it breaks free of the Pyxis.

While receiving treatment in the Silent City, James, Cordelia, and Matthew sneak in and talked with Christopher.

Meanwhile, Thomas searches the Chiswick grounds for the root and Lucie wanders off to a shed, where she spies on Grace Blackthorn.

It scoffs at her for removing James' bracelet and reaches out to destroy Jesse's coffin when Lucie reveals herself and helps Grace fight.

Lucie and Thomas Lightwood retrieve the plant to finish the antidote for the poison Christopher had developed.

They battle the Mandikhor, but are gravely outmatched until James used his connection to Belial's realm to summon a tornado and kill it.

Unbeknownst to him, the ghost of Jesse Blackthorn gave James his last breath — which had been preserved in his locket to one day resurrect himself — saving his life.

Grace pleads for his understanding of her actions and then tells him of her mother's involvement in necromancy and her plans against Nephilim.

At the following council meeting, Tatiana accuses James of having orchestrated the Mandikhor attacks and then burning her house down to destroy her evidence.

Charles announces his engagement to Grace and later seeks out Alastair, who breaks up with him in a lone corridor with Cordelia there to support him.

Magnus Bane finds Matthew feeling desolate, as he notices the younger boy looking towards James and Cordelia dancing merrily.