Cynthia Dern

Cynthia Dern (aka Allison Porter, aka Allison Goldman) was the true main villainess from "Ghosts," episode 1.08 of Castle. She was part of an eco-terrorist group that consisted of Jared Swanstrum and Susan Mailer, and after the Exxon Valdez Oil Spill, the three of them colluded to plant a bomb on an oil tanker. Swanstrum built the bomb, while Cynthia and Susan planned to plant the bomb.

However, the ship's captain, Sam Pike, got on board after the bomb was placed, causing a snag in the plan. Susan wanted to go back and defuse the bomb, not wanting harm to come to Pike, but Cynthia wanted the plan to go through and escaped while Susan went back. The bomb went off, crippling Pike and (assumingly) killing Susan.

Cynthia's true evil colors showed themselves after the events, as while she went into hiding, she sent an anonymous tip to the FBI and turned in Swanstrum. She later changed her name to Allison Porter, taking the identity from a three-month old baby who died in 1963, and met and married Michael Goldman.

20 years later, Cynthia (who was facing financial problems) went public with her version of the events, working with ghost writer Lee Wax to pen a book about the bombing. She was paid a few hundred dollars a week, with a big jackpot if her book became a best-seller. Cynthia painted herself as a hero in her story and placed all of the blame on former cohort Susan; depicting Susan as a maniacal villainess hellbent on bombing the tanker.

However, to Cynthia's surprise, Susan had survived the bombing, though she was facially scarred. Susan had learned about Cynthia's book and her twisted version of the events, and she came out of hiding and warned Cynthia in a phone conversation that she would turn herself in and reveal the entire truth. Needing to keep her ruse alive, the evil Cynthia plotted to kill Susan, first by inviting her to her hotel room for drinks. She spiked Susan's glass and then filled the bathtub with oil, planning to drown Susan. Her plan was to make it appear that the "villainous" Susan committed suicide out of guilt. Susan turned down the wine, stating that she doesn't drink, and became suspicious of Cynthia's motives. After seeing the tub filled with oil. Susan realized Cynthia's evil plan and fought with her, ending with Cynthia knocked unconscious and later drowned in the tub by Susan.