Story
Seishiro Nagi, a second-year high schooler, thought everything was a pain and lived his life in an apathetic fog. That is, until he met Reo Mikage and they entered the mysterious striker training center, Blue Lock... A new spin-off from Blue Lock's author, Muneyuki Kaneshiro, telling the story from Nagi's point of view!
Synopsis via AniList (English).
Preview
From the anime adaptation: BLUE LOCK THE MOVIE -EPISODE NAGI-.