Kanako (Kana Mochizuki), the proprietress of "Tachibana," a long-established hot spring inn in a rural town, finds herself in fierce rivalry with Fujido, the owner of the competing inn "Fujinoyu." Ultimately, she falls into Fujido's hands and is captured. Imprisoned underground, Kanako is forced into the role of a hospitality slave and subjected to intense training. As her mind and body gradually transform through the ordeal, she evolves into a new existence. Her inner desires and resistance intertwine, driving the story toward shocking new developments.