Police Lt. Cloe Anna Mills begins investigating the Headless Horseman after he beheads her friend and father figure Sheriff August Corbin. Cloe's investigation reveals the presence of two occult groups-one for good, the other evil-in Sleepy Hollow, both of which are concerned with the Four Horsemen and the associated apocalypse. The killing spree the Horseman embarks on causes Ichabod Crane and Cloe Mills to team up, especially when they find out that they are destined to be the two witnesses, the only ones who can protect the world from the forces of Hell and the Four Horsemen.