While Abbie and Sophie try to deal with a 400-year-old monster while on an FBI field exercise, Ichabod investigates the symbol while Joe and Jenny try to recover a fragment of Pandora's Box at auction.

Pandora betrays the Hidden One when she realizes that he will never consider her as an equal, and makes her stand with humanity. Meanwhile, Ichabod and Abbie realize that the Founding Fathers' flag--the one that Betsy created--holds the key to returning to the Catacombs and seek it out... putting a deadly guardian on their trail.