What will happen in "Graduation"? (#4.23)

¿WHO WILL TAKE THE CURE? - Graduation's day, Mystic Falls is full of ghosts with intentions of settling old scores and the fulfillment of their supernatural destiny. Damon's life is in danger after a ghostly meeting, while Matt and Rebekah join forces to fight a ghost decided to find the cure. When everyone gathers the graduation ceremony and the ghosts converge, appears the help of a hero. Caroline receives an emotional and unexpected graduation gift, and Bonnie plans to close the veil. Elena makes a decision about the Salvatore brothers and faces an epic confrontation with Katherine. Finally, Stefan discovers a horrible thing about the mystery that surrounds Silas. Chris Grismer directed the episode written by Caroline Dries and Julie Plec.