The narrative opens in the province of Echizen, where the young farmer Yamada Kwacho secures the favor of the local daimio after saving his life. Following a brief courtship with a local maiden named Ohano, Kwacho leaves on an official mission to Yedo, during which his young bride is kidnapped by the decadent Prince of Nijo. Rescued months later by the daimio's intervention, Ohano gives birth to a daughter named Masago, while the Prince's official consort gives birth to the Princess Sado-ko. Years later, Sado-ko lives in strict seclusion at a summer villa under the care of the Empress Dowager, shielded from the turbulent political changes of the Meiji Restoration.
Following the Dowager's death, Sado-ko is removed to the capital, where she finds herself surrounded by courtly intrigue and pressured to adopt modern Western customs she despises. Meanwhile, Masago grows up in Tokyo as the daughter of the now wealthy merchant Kwacho, chafing against the limitations of her middle-class upbringing and harboring secret ambitions for aristocratic life. When Masago is betrothed to the talented young sculptor Kamura Junzo, she travels to Kyoto for schooling, eventually crossing paths with the courtly elite through her striking resemblance to Princess Sado-ko.
Junzo, meanwhile, becomes entangled in the complex social machinery of the capital while executing a statue of Prince Komatzu, finding himself drawn irresistibly into the orbit of Sado-ko. As political tensions rise and court gossip intensifies around Sado-ko's resistance to a match with Komatzu, the two young women orchestrate a clandestine meeting during a foggy night in Kamakura. Recognizing their shared parentage as daughters of the Prince of Nijo, they impulsively execute a complete exchange of identities, allowing Sado-ko to escape the gilded cage of court life for a simple existence while Masago steps into the role of a royal princess. The deception survives the immediate scrutiny of their families and the imperial court, leading to unforeseen emotional complications as Junzo struggles to reconcile his shifting affections between the woman he thought he knew and the reality before him. As the truth finally begins to unravel through unexpected encounters and lingering memories, both women must confront the consequences of their exchanged destinies. The story concludes on a note of cautious resolution, suggesting that true fulfillment lies in self-acceptance rather than inherited status.
