Arnée Brillhit is the Western Empire's hero and most skilled swordmaster, dedicated to serving her nation. However, to her mother, Arnée is primarily the daughter of a distinguished duke—exceptionally beautiful yet still unmarried. Her mother simply wishes for her free-spirited daughter to find true happiness through mutual love. When Grand Duke Cassian Ternuzen of the Northern Empire arrives to choose a bride from the Western Empire, Arnée's unique personality makes an impression, leading him to ask for her hand. Although Arnée has no desire to marry, her mother begs her to endure the arrangement for just three months; if she thoroughly dislikes married life, she may divorce and return home. Fearing that Cassian would reject a knight, Arnée keeps her occupation secret and behaves like a frail, gentle lady—though Cassian's attention and coddling might not be entirely unwelcome after all.