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.

Ichabod enlists Henry Parrish to help him communicate with Katrina, but in the process, a menacing danger is unleashed from purgatory.