In an alternate version of the early 20th century, technological progress took a different path centered on advanced steam power, blanketing the Japanese city of Kyoto in soot and smoke. It is the summer of 1907, the 40th year of the Meiji era. The world dreams of a coming Age of Electricity, but that future feels distant and impossible to some. In the Fushimi area of Kyoto lives Inako Momokawa, the clumsy and diffident fifteen-year-old second daughter of a sake brewer. Her days are filled with scoldings from her stern father, and her only solace comes from her devout prayers to the gods, while she secretly harbors the dream of following her deceased mother’s footsteps to become a head brewer.

Her life changes when she encounters Kihachi Sakamoto, a freewheeling young man who rejects the gods and openly boasts about the incoming age of electricity. Kihachi was once a dreamer who, together with his admired older brother Seiroku, chronicled their visions for an electric future in a unique notebook called the 20th Century Electrical Catalog. However, Seiroku took the catalog and left for war, never to return. The loss of his brother shattered Kihachi’s dreams, leaving him distrustful and cynical about the future he once believed in.

When Inako’s father unilaterally decides to force her into an arranged marriage, she is on the verge of giving up all hope. Kihachi steps in, drawing out her true desire to escape her family. The only way to stop the marriage is to find the lost Electrical Catalog, a book that holds the secrets of the future they both long for. Together, Inako and Kihachi set off on a journey across Kyoto and Shiga prefectures to locate the missing manuscript. Along the way, they must confront their painful pasts—his grief and her hidden regrets over her mother’s death—while carving a path toward the revolution of an electric tomorrow. Their search draws them into conflict with powerful interests, including Yosuke Mizoe, the heir to a major steam engine company who is politically engaged to Inako and who harbors his own secrets connected to Seiroku. The series follows these two young protagonists as they explore the mysteries of the catalog, challenge a world resistant to change, and fight to reignite the dream of a brighter future.