With old enemies gone, Abbie and Crane are apparently moving on with their lives. However, the discovery of a mysterious tablet shows that there may be a new dark prophecy surrounding our Witnesses. The two team together, with the help of an old amulet, and continue their epic takedown of the forces of evil.

In the aftermath of Jenny and Joe's run-in with Sophie, Abbie is in deep water with Reynolds. Meanwhile, the Witnesses deal with lasting implications of the shard and find themselves in grave danger as they come face-to-face with a greater evil than they could have imagined.

In the quest to save Abbie, Crane and Sophie are forced to battle a supernatural force targeting the citizens of Sleepy Hollow, while Pandora and The Hidden One only grow stronger. Meanwhile, in an effort to find out what truly happened to her sister, Jenny faces an old foe: her father. Can our heroes solve their most personal case yet?

When Jenny makes the decision to confront her father, family turmoil from the past rises to the surface. Meanwhile, Atticus Nevins returns to town, bringing more danger than the FBI could have imagined.

On an FBI team-building day, Abbie and Sophie come face to face with a monster that may finally blow their cover with Reynolds. Meanwhile, Jenny and Joe find themselves in possession of something precious and Crane discovers that the symbol from the Catacombs may be more important than he realized.