The Beast Within – Halloween is plagued with a demon outbreak in New York City.
Heavenly Fire – Simon and Izzy team up on a secret mission to figure out what the Clave is hiding; Clary becomes conflicted about Jonathan as the Shadowhunters try to get answers.
Stay With me – Clary and Jace comes up with something that would help against her twinning rune. Meanwhile, Alec keeps worrying about Magnus.
To the night children – Consequences put some rules in question.
A Kiss From a Rose – Isabelle asks Alec for help. Magnus asks Lorenzo for a favor. Jace takes Clary on a date.
Beati Bellicosi – Jordan and the Praetor try to track down Heidi, while the Shadowhunters try to locate Jonathan. Meanwhile, Luke looks to Maryse for help and Isabelle gets a possible lead on information on what is really going on in the Clave prisons.
Original sin – Simon is determined to get rid of the Mark of Cain and, with Isabelle’s help, tries to track down New York’s oldest vampire to get more information on the mark.
Lost souls – Alec, Isabelle and Jace try to come to terms with the apparent loss of Clary; Magnus mourns the loss of his magic and must rely on others for help; Maia tries to help a devastated Simon; Clary finds herself in a new and dangerous predicament.
Erchomai – In the Season 3 midseason finale, the team scrambles to find a way to put a stop to Lilith’s plan coming to fruition. Meanwhile, Simon makes a heartbreaking choice with Isabelle’s help and Magnus reconnects with a powerful person from his past.
Familia Ante Omnia – Clary faces down an old foe in an attempt to find answers about Lilith’s plan. Alec and Magnus turn to Lorenzo Rey for help, while Lilith finds a new ally. Luke must choose between his pack and his family, as Simon is forced to deal with his past.