All Good Things – Jonathan begins his reign of vengeful terror as the Shadowhunters try to find a way to stop him. With only one hope, Clary must make a sacrifice that could have long-lasting implications for all. Meanwhile, wedding bells are in the air for one special couple.
City of Glass – Alec, Jace, and Isabelle attempt to get Clary back. Maia has to make a tough decision.
The Beast Within – Halloween is plagued with a demon outbreak in New York City.
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.
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.
Salt in the Wound – With the Owl’s identity revealed, Alec, Isabelle, and Clary head to Alicante to try and find a way to stop him. Luke and Simon team up to track Lilith’s latest possible victim. Maia reflects on her past.
A Window Into an Empty Room – Clary teams up with Magnus to investigate a recent demon attack. Simon is stunned with he’s visited by someone he never thought he’d see again, and who now won’t seem to leave. Meanwhile, Izzy worries about dinner with her family and a special guest and Luke reaches out to Maryse.