It's Prom night in Chance Harbor and after Adam (Thomas Dekker) uncloaks a crystal hidden in the school, Blackwell (guest star Joe Lando) tells Cassie (Britt Robertson) she can use her dark magic to find it. When Cassie follows this advice, it leads her to a dangerous discovery. Meanwhile, Faye (Phoebe Tonkin) invites Jake (Chris Zylka) to Prom, despite the fact that he stood her up two years earlier. Adam, Diana (Shelley Hennig), Cassie and Melissa (Jessica Parker Kennedy) finally make it to Prom but when they lose the crystal to Eben, they end up in a life and death situation. Meanwhile, Dawn (Natasha Henstridge) attempts to stop Blackwell, who casts a deadly spell on Charles (Gale Harold).
