Yokohama Kaidashi Kikō is set in a peaceful, post-cataclysmic world where mankind is in decline after an environmental disaster. Exactly what happened is never explained, but sea levels have risen significantly, inundating coastal cities such as Yokohama, Mount Fuji erupted in living memory, and climate change has occurred. With the seasons being less pronounced, the winters are milder and the summer isn't scorching anymore. The reduced human population has reverted to a simpler life, and the reader is told this is the twilight of the human age. One scene depicts an anti-aircraft missile being used in a firework display. Instead of raging against their fate, humans are quietly accepting.[5][6]
Alpha Hatsuseno is an android ("robot person") who runs an out-of-the-way coffee shop, Café Alpha, on the lonely coast of the Miura Peninsula of Japan, while her human "owner" is on a trip of indefinite length.[7] Though she spends much of her time alone, Alpha is cheerful, gregarious, and—unlike the slowly declining humans—immortal.[6]
Most chapters of Yokohama Kaidashi Kikō are self-contained slice-of-life episodes depicting Alpha in daily activities, either alone, with customers, or on occasional trips through the countryside or into Yokohama for supplies (whence the "shopping log" of the title came). Whole chapters are devoted to brewing coffee, taking photographs, or repairing a tiny model aircraft engine, sometimes with only a few lines of dialogue. Through Alpha's experiences, the author brings out the small wonders of everyday life and makes the reader aware of their passing: [...]. In evoking a nostalgia for this loss, Ashinano follows the Japanese tradition of mono no aware (sadness for the transience of things).[8]
Though often self-contained, the stories have continuity—relationships grow and change, and seemingly insignificant details reappear later.[6][7] Ashinano explains few details of Alpha's world, leaving mysteries that engage the reader[9] as the series unfolds in a meandering progression, by turns funny, touching, and nostalgic.[10][11]
