This is a superhero action story about a boy born as a "Knocker," a person with unusual superpowers, who becomes a special member of the anti-Knocker unit "BOOTS" and fights for justice. Kou Tatsumi, a middle school student who was born as a Knocker and grew up ostracized by those around him, is forcibly taken to the police station by Inspector Kirihara and BOOTS female member Yamato before going to school. There, Kou learns that he is the only person compatible with the new booster "Specialized Type 19," and is called upon to participate in a mission to recapture the Metropolitan Police Department building, which has been occupied by a masked man named Shrike...!?