After the mysterious death of an art restorer at the Sleepy Hollow Historical Society Soiree, Ichabod and Katrina are reminded of a dear friend from their past - Abigail Adams. Meanwhile, Abbie is shocked by someone's visit to the police precinct.

After escaping Purgatory, a warlock who triggered the Salem witch trials returns to find a dangerous book of spells. Meanwhile, Abbie attempts to trust Frank Irving again, while Henry struggles to find his identity.