Still adjusting to his 21st century reality, Ichabod Crane and Det. Abbie Mills move forward in their mission to unravel the mysteries lurking in Sleepy Hollow. A frightful vision from Ichabod's former wife Katrina, sends the unlikely duo on the hunt for a vengeful witch from the 1700s who has been awoken by unknown evils and is on a path of destruction in the quaint town. Meanwhile, despite all odds, Officer Andy Brooks is back and on a questionable mission of his own.

Another soldier in the army of evil, the Sandman, seeps into the dreams of the residents of Sleepy Hollow. By infiltrating their minds at night, he tortures them to the brink - all because they, at one time, turned a blind eye to justice. When the Sandman seemingly sets his sights on Abbie, she is forced to begin to face her past - and her institutionalized sister Jenny. With Ichabod by her side, and her life at stake, the duo must try to defeat the Sandman and continue their fight against evil.