Clary books a show for Simon to perform his music. He's hesitant, but she confronts his worries. Maia and Jace watch on in discomfort.
The dead body of a Shadowhunter is discovered in an alleyway.
Vampires want to join up with Simon and have him lead them in a new clan. He declines as he only wants a normal life.
The Inquisitor brings in Luke for questioning about the murder. The others are positive he didn't do it, but a werewolf did commit the crime. The Inquisitor plans to name Jace as the new head of the New York Institute.
More bodies of dead Shadowhunters are being found. This time, they were cut with a Seelie blade and a warlock attack. The group goes out to ask for DNA from their friends; Alec has an uncomfortable encounter when he asks Magnus.
The mysterious killer attacks Clary. She's about to be kidnapped until Simon finds her body.
Dot comes to visit Magnus and gives him dragonfly wings. He won't talk about what he's making him upset.
The Inquisitor and the Clave plans to chip all the Downworlders after another body is discovered. Alec is against the whole idea and Simon is placed in a cell when he won't leave an unconscious Clary.
Jace enters Hunter's Moon to chip the Downworlders, but Maia resists and starts fighting them. Maia gets chipped before Luke is able to break it up.
It's revealed Dot and Magnus hooked up nearly a century ago.
Maia is arrested and brought to the jail in the Institute. The Inquisitor believes she's the one who killed the latest Shadowhunter.
Raphael reveals to Isabelle that a Seelie once admitted to Camille that the best way to show revenge against the Shadowhunters was to take their runes. That Seelie was Meliorn.
Jace and Clary free Simon and Maia from prison.
Raphael and Isabelle find Meliorn standing over a dead Shadowhunter. Seelies don't lie, so they believe him. But Isabelle's brother Max has gone missing.
The killer is Kaileigh, the Seelie girl from earlier who poured the drink on Jace. She did it in retribution for the Shadowhunters causing her brother's death.
Jace decides to pass on the title of head of the NYC Institute to Alec.
Simon performs his music at Hunter's Moon.
Jace removes the chip from Maia and the two make-out.