It is the 6th year of the Taisho era (1917). Koyuki's parents died when she was very young, and she and her twin sister were taken in by her wealth-seeking aunt and uncle, who treated them like servants. When her sister falls into a coma, she is married off to Yuichiro, the son of the Morisawa Zaibatsu, who is rumored to be a violent man. Koyuki and Yuuichiro become a married couple under the guise of her sister Koharu. Koyuki wants to understand Yuichiro as his wife, even if only in a formal sense. Yuichiro, on the other hand, is puzzled and moved by his wife's modesty and purity, which he had thought to be showy..