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.

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.

After a supernatural event takes the Witnesses by surprise, both Crane and Abbie are forced to work alongside their most hated foes yet. Meanwhile, Jenny and Joe struggle to salvage their relationship, as they continue to battle their own internal demons.