The time is the Taisho era. The orphan Meiko, who suffers from weak eyesight, lives a modest but peaceful life at a temple orphanage.

One day, a suspicious person visits the temple and suddenly attacks Meiko. When she wakes up, she finds that time had rewound several months back. To avoid death, Meiko follows a guide. There she meets her long-lost twin sister, Kanako, the daughter of a marquis. After her parents tell her the story of her birth, Meiko is to marry Matsuwaka Akashi, a military man feared as the "Demon Akashi," as Kanako's substitute.

(Source: Kadokawa, translated)