After the attack, the Institute and The Clave are on high alert and taking no prisoners to get answers. When Lydia makes a harsh call on the Seelies, Jace, Clary and Isabelle fear that this decision could be disastrous and the wrong way to defeat Valentine. Left with no other choice, the trio takes drastic actions to stop what is about to take place.

Meanwhile, Simon struggles to deal with his new situation, and Alec is emotionally torn with what is happening at the Institute.

Clary and Jace get a tip from Meliorn that they can find Valentine by locating a portal in another dimension, but only Clary can venture into this new world. What Clary finds in this alternative universe is that life there is as if the threat of demons no longer existed and Shadowhunters were no longer needed. While she realizes that this dimension is the life she always dreamed of, Clary must act fast or she will lose herself in the alternative world forever.

Meanwhile, Alec and Isabelle must face the consequences of the Downworlder attack.

After receiving important intel about Valentine from a surprising ally, Clary, Jace and Luke devise a plan to rescue Jocelyn. With the mission looking almost impossible, the three will stop at nothing to rescue Clary’s mother and put a stop to Valentine once and for all.

Meanwhile, Inquisitor Herondale arrives at the Institute for Isabelle’s trial as Alec turns to Magnus for help.

Tasked with arranging his brother Max’s Rune Ceremony, Alex decides this would be the perfect opportunity for his family to get to know Magnus. But with tensions flying among the different Shadowhunters, Max’s big event quickly becomes an evening where they all must face their biggest fears. Meanwhile, Simon makes a bold move as Isabelle finds an unlikely new ally.