Airi travels across a post-apocalyptic Japan on a Yamaha Serow motorcycle, having recently emerged from an underground bunker. Her journey represents a first encounter with the authentic culture of the surface world. Her name is written in katakana, indicating she is not a native Japanese individual in the traditional sense.

Reserved and knowledgeable, she often shares information about the world, acting as a teacher for her companion and the reader. Though generally cautious, she shows a clear preference for surface food over bunker rations. Her journey is driven by discovery and optimism, though the harsh environment continually tests their survival skills.

Her knowledge is sometimes paired with immaturity in dangerous situations, creating a disconnect between their approach and the severity of the threats. Still, she and her companion navigate hardships with a playful attitude, often making light of their circumstances.

A central mystery involves her reference to a robot as human, suggesting a deeper relationship between humanity and technology. Their bunker also had internet access, adding further intrigue to her background. Their journey follows a radio signal in an attempt to find another human voice, highlighting the emptiness of the world they explore.