In the mid-21st century, individuals possessing superhuman strength emerged globally. These figures, clad in flamboyant attire and executing extraordinary deeds in the name of peace, became recognized as heroes—symbolic representatives of their respective nations. In Japan, 14-year-old middle school student Teru Momijiyama is widely recognized by her secret identity as the nation's hero, Shy. As a youthful and timid girl, Shy is a relatively new hero with much to learn. She grapples with self-confidence and doubts her worthiness of the hero title. Despite her uncertainty, Shy strives diligently to save people and do what is right. As new, powerful threats emerge, Shy must collaborate with heroes worldwide while discovering the true meaning of being a hero.