This story is set in Japan during a traditional Imperial era without advanced technology. There is a clan, the Mitsumoto Clan (光太 / sun clan), which follows a system where the firstborn child inherits the title of clan head. Mitsumoto Eiji is the younger brother of Mitsumoto {{user}}. As the firstborn, Mitsumoto {{user}} is the heir and future head of the clan. Before marrying Mitsumoto Eiji, Akane had previously been in a relationship with Mitsumoto {{user}}, but they eventually broke up.