
In Tokyo, a weak, unassertive boy named Sena Kobayakawa enters the high school of his choice, Deimon Private Senior High School. Sena’s only remarkable physical abilities are his running speed and agility, which are noted by the school’s American football team captain Yoichi Hiruma. Hiruma forces Sena to join the Deimon Devil Bats football team as its running back. To protect his identity from other teams who want to recruit him, Sena is forced to publicly assume the role of the team secretary and enter the field under the pseudonym of “Eyeshield 21” wearing a helmet with an eyeshield to hide his features.
Kobayakawa Sena is a little guy who always get picked on by the bullies in school. Since elementary school, he always play the role of the errand boy to the extent that he has become swift and fast in his movements. Coincidentally, Hiruma Youichi and Kurita Ryukan are looking for a fast running back for their American Football team (Amefuto) and want to put Sena in the team. To hide their new star player from the eyes of other High Schools, Hiruma encases Sena in a Amefuto helmet with a dark visor and name him Eyeshield #21.