Serien handler om Ichabod Crane, der dør under den amerikanske uafhængighedskrig i 1781, men under mystiske omstændigheder genopstår i Sleepy Hollow, New York i det 21. århundrede.

Han finder til sin forbavselse ud af at hans ærkefjende fra det 18. århundrede, Den Hovedløse Rytter, har taget samme tur. Det var Ichabod Crane, der huggede hans hovedet af før han selv døde og nu er Den Hovedløse Rytter begyndt at sprede skræk og rædsel om natten i Sleepy Hollow, hvor han blandt andet hugger hovedet af den lokale sherif.

65 million years ago, the knights of the Ryusoul Tribe were selected to participate in a war campaign against the dictating Druidon Tribe who sought to rule Earth. But the Druidon's war campaign was halted by the meteor that brought the age of the dinosaurs to an end, forcing them to flee into space. Meanwhile, the Kishiryu were placed in a deep sleep as a failsafe should the Druidon return. The chosen knights choose to live in peace while passing their mantle down across generations. In the present day, the Druidon return to reclaim Earth as the current generation of knights, the Ryusoulgers, battle them with the support of Ui Tatsui and her father Naohisa Tatsui.

When a group of archaeologists uncover the tomb of a legendary warrior, they unearth Kuuga’s belt, accidentally releasing an ancient race of monsters called the Grongi, bent on destroying humanity. Enter Yusuke Godai, a modern-day guy next door, who learns he is telepathically linked to the mysterious stone belt. With its power, he transforms into the legendary warrior known as Kuuga, humanity’s only defense against the murderous Grongi monsters.