After her battle against the mysterious organization Amarariruku, Teru Momijiyama returns to her regular life in Tokyo—all while secretly continuing to save people as Japan's hero Shy. As a result of her experiences with others, Teru is able to slowly gain confidence in herself. While she still has a long way to go, Teru continues to make progress toward learning what being a hero truly means.

While walking around the city after school, Teru runs into Ai Tennouji, whom she quickly befriends and begins to open up toward. Teru quickly learns more about her new friend's past—she has run away from her village in search of something directly related to Teru's work as Shy. While the threat of Amarariruku continues to loom over her, Teru must decide how closely she is willing to work with the mysterious Ai.