When an unidentified boy is discovered in Sleepy Hollow, Ichabod Crane and Lt. Abbie Mills are called to the scene. After speaking with the child, they immediately realize that something sinister and sickly is afoot and the duo go on a hunt to discover his home and origins - and are shocked by what they find.

Ichabod, Abbie, Capt. Irving and Jenny Mills unite against the Headless Horseman; information about the Horseman's motive shocks Ichabod.

When Capt. Iriving's daughter, Macy, becomes the target of evil forces, he makes a desperate plea to Crane and Mills for help, and seeks answers that lie within Washington's Bible. Meanwhile, a frightening chapter of Jenny's past is revealed.

When Pandora unleashes an iconic monster to haunt the residents of Sleepy Hollow as they sleep, Abbie and Jenny are tempted to confront a painful part of their past. Meanwhile, Abbie makes a crucial decision for her career and Crane does his best to guide her with wisdom from his own experiences. Will Ichabod lead Abbie to the right decision?

Following Abbie's huge sacrifice, Crane and Jennie find themselves at a loss. In an effort to save Abbie, Crane forms and unlikely partnership and Jenny confronts a former foe.

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.

After a startling discovery, Abbie and Crane realize what they must do in order to make Pandora’s box complete again. Meanwhile, the team works tirelessly to stop The Hidden One, before he destroys all of humanity. Can the Witnesses succeed with the fate of the world in their hands once again.