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.