In a near-future Japan, global warming has submerged the great city of Yokohama beneath the ocean, leaving only the hills above the water. What was once one of the country's largest cities now feels like a small town, and the very existence of the island nation has been threatened. Yet there is no sense of desperation, devastation, or hopelessness. People live relaxed lives, cherishing each other's company and enjoying quiet, peaceful moments together.
This is especially true for Alpha, a carefree young woman who runs a cafe called Cafe Alpha. She immerses herself in the beautiful nature around her, finding joy in spending quality time with her kind friends. The fulfillment and happiness she finds in life suggest she is a compassionate human being—but she is not quite human. She is actually a type A7M2 robot.
One day, a radio forecast warns of an approaching typhoon. Her old friend, who runs a nearby gas station, invites her to take shelter there, worried that her aging cafe might not withstand the storm. The typhoon does indeed pass, leaving Alpha's cafe severely damaged. That prompts her to embark on a journey to raise money for rebuilding, and also to see the outside world beyond her friends and the comfort of a peaceful life.