At twelve years old, Maple Akimura's future has already been decided. With her mother insisting she become an apprentice at the family apothecary business, Maple sees a small life in her village ahead of her.

Maple would rather spend her time with Kunio, her new friend visiting from Taisho City, than study her family's history. Her mother insists she reads the family book detailing the Akimuras' relationship to yokai (spirits and supernatural beings) over generations. To Maple, the stories of the yokai are just a remnant of traditional village living, amid 1920s Japan's rapidly advancing technology and the glamor of modern urban life--especially in bustling Taisho City. But Maple's encounter with a mischievous yokai named Ember sweeps the pair into the hidden spirit world, with only Maple's family stories to guide them.

Now, they must navigate hidden dangers, strange creatures, and dark secrets to send Ember home and empower Maple to find her own path.