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.