"Konna Watashi-tachi ga Nariyuki de Heroine ni Natta Kekka www 'Narihero www'" centers around three ordinary high school girls—Hiyori, Ruriko, and Satsuki—whose lives take an unexpected turn when they are thrust into extraordinary circumstances. The narrative begins with the trio discovering a mysterious app on their phones that grants them the ability to transform into magical heroines. This app, known as "Narihero," is tied to a parallel world where they are tasked with protecting their reality from interdimensional threats. Each girl is assigned a unique magical persona, complete with distinct powers and costumes, reflecting their individual personalities and strengths.

Hiyori, the most level-headed of the group, becomes the leader, wielding powers of light and strategy. Ruriko, cheerful and energetic, gains abilities tied to nature and healing, while Satsuki, the reserved and intellectual member, commands technology-based powers. Together, they must balance their everyday lives as students with their newfound responsibilities as heroines. The story explores their growth as they face increasingly dangerous adversaries, each battle testing their teamwork and resolve.

The plot delves into the origins of the Narihero app, revealing it was created by a mysterious organization to combat an ancient evil threatening both worlds. As the girls uncover more about their roles, they encounter allies and enemies, including other heroines and rogue entities seeking to exploit the app's power. The narrative also examines the personal struggles of the main characters, such as Hiyori's self-doubt, Ruriko's fear of inadequacy, and Satsuki's difficulty connecting with others. These challenges are interwoven with the overarching mission, adding depth to their character development.

The series balances action, comedy, and drama, with the girls often finding themselves in humorous or awkward situations as they navigate their dual lives. The interplay between their ordinary high school experiences and their heroic duties creates a dynamic contrast, highlighting their relatability despite their extraordinary circumstances. The story concludes with a climactic battle against the primary antagonist, resolving the central conflict while leaving room for potential future developments. Throughout, the series emphasizes themes of friendship, self-discovery, and the courage to embrace one's destiny.