**SPOILER ALERT** DON'T READ IF HAVEN'T SEEN MID-SEASON FINALE!!!
In the 2nd hour of the mid-season finale of Shadowhunters season 3, Simon and Clary had a plan to get rid of Lilith:
Simon gave Clary a stele, (Alec you saved the world!), and hid. Clary then told Lilith she would kill herself (with the stele), so her brother would not return. While Lilith was focused on Clary, Clary said, ''Simon Now!'', and Simon speed in with his super cool vampire speed and started hitting the glass in the place Johnathan's body was and Lilith screamed and tried to kill Simon, forgetting completely about the Mark of Cain and focused on saving her son. When she tried to do this, the Mark of Cain hit her sevenfold, or seven times as worse as she was going to do to Simon. When the Mark of Cain acted on Lilith, it struck her with a heavenly source, banishing her back to Edon, A.K.A Hell. There was an explosion while Simon was being thrown threw a window and Clary was running to help him but she did not get there in time and the explosion ''Killed Her''. As for Simon, he grabbed onto the side of the building and climbed up back to the top where the explosion was. That is when he was confronted by Jace, finally out of Lilith's hold on him, and Jace asked him where was Clary. Simon said ''She's Dead.'' Jace then started crying and I think that Dominic Sherwood pulled off that moment great! In this moment of the episode he is facing the death of the person he loved the most which is hard on anyone. I cannot wait for season 3B to return!