Steve McGarrett returns home to Oahu, in order to find his father's killer. The governor offers him the chance to run his own task force (Five-0). Steve's team is joined by Chin Ho Kelly, Danny "Danno" Williams, and Kono Kalakaua.
Ichabod Crane awakes from the throes of death 250 years in the future where he must solve a mystery dating back to the founding fathers. Due to a blood spell cast on a battlefield during the Revolution, the infamous headless horseman is revived along with Crane, and the murderous rider embarks on a bloody rampage in present-day Sleepy Hollow. Ichabod realizes that he must act quickly, for the headless horseman is only the first of the Four Horsemen of the Apocalypse. Detective Abbie Mills, a woman familiar with supernatural experiences, forms a bond with Crane as they try to stop an increasingly vicious cycle of evil.
The series follows a Federal Bureau of Investigation "Fringe Division" team based in Boston. The team uses unorthodox "fringe" science and FBI investigative techniques to investigate a series of unexplained, often ghastly occurrences, some of which are related to mysteries surrounding a parallel universe.