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.

Lt. Abbie Mills and Ichabod Crane search for Abbie's estranged sister, Jenny Tag Team, who has escaped from a Sleepy Hollow psychiatric hospital. In a game-changing episode, which includes flashbacks to the real Boston Tea Party, Abbie and Ichabod discover more about the evil they are facing... and finally learn its name in the haunting.

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.

When Ichabod Crane goes missing, his wife, Katrina, appears to Lt. Abbie Mills in a vision warning her that the Headless Horseman will return to Sleepy Hollow by nightfall. A frantic Abbie seeks help from the mysterious Henry Parrish, who holds vital clues about how Crane can vanquish his dangerous blood tie to the Horseman. Meanwhile, an encounter from Crane's past weighs heavily on him, and details about his first encounter with Katrina are revealed.

Abbie and Ichabod look for clues to stop the evil in town; Abbie receives an unexpected visit from Andy Brooks.

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

When Ichabod and Abbie investigate a missing persons case, the search leads to a colonial-era house which holds secrets from Ichabod’s past...and unleashes a long-dormant evil.

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