1781年，美国独立战争期间。乔治·华盛顿麾下的伊卡博德·克兰上尉（汤姆·米森 Tom Mison 饰）在战场上砍掉了一个手执利斧的面具骑士的头颅，自己也身负重伤失去意识。当他再度醒来，发现周遭早已翻天覆地，此时他正处在250年后的现代化美国社会。与此同时，断头谷治安官被残忍杀害，他的搭档艾比·米尔斯（妮可·贝哈瑞 Nicole Beharie 饰）意外邂逅伊卡博德，进而得知杀害治安官的正是阴森的无头骑士。伊卡博德了解到妻子卡特里娜（卡蒂亚·温特 Katia Winter 饰）在他受伤后所做的一切，并从圣经的记载中意识到邪恶的天启四骑士即将和来自地狱的邪魔军团莅临人间。在此之后，死亡和杀戮在断头谷肆意蔓延，女巫、血咒、恶魔，种种鬼魅迷雾萦绕着美国的历史，从古至今，影响深远……本片根据华盛顿·欧文创作的《断头谷传奇》改编。
On a revolutionary battlefield Ichabod Crane meets and kills the Horseman of Death. But in doing so he is mortally wounded. In order to save his life, his wife, a witch, with the help of warlock, Reverend Knapp, link Ichabod to the horseman of death. Over 200 years later, an evil force awakens the now headless horseman. While stealing a horse from a barn, he is confronted by the sheriff of Sleepy Hollow, who is shocked to see that the shadowy figure in the barn lacks a head.
Lt. Abbie Mills, of Sleepy Hollow who was with the Sheriff, but is charged with finding the owner of the farm, comes upon the owners headless body. She runs to warn the sheriff, but its too late and he too is beheaded. She realizes that the murderer is sitting on a pale horse with no head and an odd branding on his hand.
Because Ichabod is linked to the horseman, he also awakes. The shock of going from 1781 to 2013 brings him to the notice of police officer Andy Brooks, who takes him into custody for the murder of sheriff Corbin. He tries to explain who he is, but that lands him in a psych ward.
While digging into the sheriffs secret files, Abbie realizes that Crane is telling the truth. That the horseman of war is indeed on earth and he's soon to be joined by the horseman of famine, war and conquest. And that it is their job to stop this from happening.
