Henry sets out to find the Gehenna Key, which will allow his master Moloch to escape from Purgatory with an army of the damned. Meanwhile, Ichabod tries to free himself from his buried tomb, and Jenny must escape the Hessians holding her on Henry's behalf.

After a bank robbery turns violent, Abbie and Ichabod embark on a hunt for a mysterious silver coin that has more power than meets the eye. Captain Frank Irving is put in the position where he must choose between his family and the greater good. The Mills' sisterly bond is put to the utmost test.

Abbie and Ichabod learn that Katrina is in imminent danger and race against the clock to help her.

Ichabod and Abbie set out to find the Sword of Methuselah, the only weapon capable of killing Moloch and ending the coming apocalypse.

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.

Ichabod and Abbie face demonic creatures that guard a secret crypt and encounter Thomas Jefferson in their quest to fight evil. Meanwhile, Jenny learns a shocking secret about Frank Irving.