Kei operates as a child superhero alongside Yoji, their activities concealed from their foster parent, Anna. They utilize handmade high-tech machinery and specialized zipper-based technology to protect their community and assist residents during emergencies.

Her heroism involves direct action against threats, from localized problems to larger crises like an out-of-control sightseeing airship endangering the town. She consistently applies the fastening technology creatively to resolve dangerous situations and restore safety, bridging divides within the community through her actions.

Kei forms a dedicated team with Yoji and a small robot bear named Oscar. Their missions demand coordination and teamwork, facing escalating challenges that test their abilities, including competition from another unidentified superhero using similar zipper-based powers. Eventually, alongside Kelly who joins their efforts, Kei participates in further rescue missions, deepening her connection to the town and its people.

While outwardly focused on protecting others, her actions also reinforce bonds within her immediate family unit, particularly her relationship with Yoji and their shared life with Anna. The narrative links their use of fastening technology to both physical repairs and strengthening interpersonal ties.