Alec, Jace and Isabelle make a plan to finally get Clary back and stop Jonathan—much to Luke's and Simon's chagrin. Meanwhile, an emotionally raw Magnus struggles to deal with his father's reappearance and Maia must make a tough decision that could affect the rest of her life.
- Katherine McNamara as Clary Fairchild
- Dominic Sherwood as Jace Herondale
- Alberto Rosende as Simon Lewis
- Matthew Daddario as Alec Lightwood
- Emeraude Toubia as Isabelle Lightwood
- Alisha Wainwright as Maia Roberts
- Isaiah Mustafa as Luke Garroway
- Harry Shum Jr. as Magnus Bane
- See more here
A list of the songs and score music featured in this episode:
- "Part of Me" - Gold Brother
- "The Push" - DYAN
- "The Ending" - Wafia feat. Finneas
- "Bridges" - Aisha Badru
- "Romance. Andante from Eine kleine Nachtmusik, K.525" - Leonard Bernstein & New York Philharmonic
- The title of the episode is a reference to Alicante—which is sometimes referred to as the City of Glass—as well as the title of the third installment of The Mortal Instruments book series.
- Some of the exterior shots set in Alicante in this episode were filmed in Paris.
- Parts of this episode was changed following the cancellation of the series and the creation of the two-part finale. This episode was originally supposed to end with a cliffhanger that was since incorporated into the finale episodes.
- "Missing our cast as they are shooting in romantic Paris this week." Kathleen Jenkins on Twitter
- "... to France to shoot exteriors the we used in 312, doubling for ... Alicante in 320." Bryan Q. Miller on Twitter
- "... the current 320 episode out was *not* the season out (when 320 was the finale)." Bryan Q. Miller on Twitter