Zuzu inhabits a remote island populated by unique anthropomorphic creatures. A native islander, Zuzu strictly adheres to the community's rules forbidding exploration beyond their shores, yet privately covets mysterious objects that wash ashore. This collecting habit leads Zuzu to find a music box on the beach, promptly shared with companions Paroru and Rikotto. Though not naturally adventurous, Zuzu is swayed by the eager Rikotto to join an unauthorized sea voyage after glimpsing a photograph of fireworks.

Accompanying Paroru and Rikotto, Zuzu marvels at the initial sights upon reaching the human world. Their exploration brings them to a bustling city, where fascination swiftly turns dangerous. Zuzu and Rikotto are captured by a circus ringleader determined to exhibit them as oddities. This imprisonment leaves Zuzu helpless, requiring rescue from outside. Paroru, spurred to overcome deep-seated fears after initially resisting the journey, intervenes to secure their freedom.

Zuzu's story traces a path from rule-following island resident to reluctant traveler on an off-island quest, culminating in vulnerability within human society and ultimate dependence on Paroru's courageous act for deliverance.