Ichabod finds himself buried alive in a coffin. Abbie is trapped in purgatory. Ichabod's wife, Katrina, is kidnapped by the Headless Horseman. Capt. Frank Irving is behind bars for a hug he did not commit. Abbie's sister is among the wreckage of a horrific car crash. Now, with Henry's emergence as the Horseman of War, alongside the Headless Horseman, Sleepy Hollow has never been so close to destruction.
To rescue Katrina from the Horseman's clutches, Ichabod comes up with a plan to use a patchwork man that Benjamin Franklin created as a weapon against the Horsemen... a weapon that may be as dangerous to the user as to the target. Meanwhile, Frank finally tells the authorities that a demon killed his supposed victims, and Katrina chooses to help Abraham in his quest to enact Moloch's plan.
After a bank robbery turns unhappy, Abbie and Ichabod embark on a hunt for a mysterious silver coin that has more power than meets the eye. Meanwhile, Captain Frank Irving is put in a position where he must choose between his family and the greater good and the Mills' sisterly bond is put to the utmost test.
Ichabod and Abbie search for a missing child, whose disappearance is related to a legend of a mysterious Piper and a family curse. Meanwhile, Irving begins to discover the price of his arrangement with Henry.
A woman from Ichabod Crane's past comes to Sleepy Hollow in the form of an un-dead Weeping Lady, aiming to harm anyone in her path. Katrina and Crane learn unsettling things about each other's pasts. Abbie has some unexpected flirtatious encounters.
Joe Corbin, the sheriff's son, returns from overseas and blames Abbie for his father's death. However, she soon learns that Joe has to pay in stopping apocalypse... or starting it. Meanwhile, Henry gives Irving the chance to win back his soul.
Katrina manages to escape after Henry seemingly poisons her, and makes her way to Abbie and Ichabod. However, they soon realize that Katrina faces a fate much worse than death. To cure his wife, Ichabod must convince Henry to use his abilities on his mother's behalf.
As part of his new plan to summon Moloch to Earth, Henry sends a succubus out to gather human life forces. Meanwhile, Ichabod and Katrina try to resolve their trust issues, and Abbie finds herself doubting her partner's wife.
A series of mysterious deaths at Tarrytown Psych leads Abbie and Ichabod to discover that an especially surprising spirit is involved.
As Moloch grows to adulthood and prepares to unleash his Horseman, Abbie and Ichabod race to find the Sword of Methuselah before the Headless Horseman can acquire it and deliver it to his master.
Ichabod and Abbie must decide whether they are willing to sacrifice themselves to hug Moloch and Henry, when they learn the cost of using the Sword of Methuselah.
Six weeks following Moloch's defeat, Ichabod and Abbie encounter an angel, Orion, that they believe can help them. At first pleased by his arrival, the pair discovers Orion - and his true motivations - may not be as benevolent as first assumed. Meanwhile, Katrina searches for the humanity in Abraham.
Ichabod and Katrina decide to have a "night out" by attending a historical society event. However, when an art restorer turns up dead, they soon discover that a supernatural menace is involved. Meanwhile, Irving turns up at the station, and Abbie sends Jenny to find a weapon capable of destroying him if necessary.
Nick's godmother appeals to him for help in stealing a mystic artifact from an impenetrable vault. To succeed, he has to betray Ichabod, Abbie, and Jenny. Meanwhile, Katrina agrees to determine if Irving is human or not.
The sorcerer who killed Katrina's grandmother escapes from Purgatory and goes on a bloody rampage. While Ichabod and Abbie try to stop him, Katrina learns why her powers have been erratic, and Henry emerges from hiding with a new plan.
Ichabod and Abbie face demonic creatures that guard a secret crypt and encounter Thomas Jefferson in their quest to fight evil. Meanwhile, Jenny learns a shocking secret about Frank Irving.
Ichabod and Abbie fight against those who want to re-awaken a powerful witch coven and Jenny learns a disturbing truth about Frank Irving.
Abbie is trapped in 1781 and must convince Ichabod that they are partners in the future. Meanwhile, Katrina convinces the Horseman to Ally with her so that she can Ichabod and change the future.