Letícia, the princess of the Winter kingdom, will marry Prince Ryuuji of the Autumn kingdom due to an old agreement between the kingdoms, but her mother left her a diary informing her that she needed to find a trustworthy knight to protect her. She finds Aleph a knight with exceptional qualities, but he hides his real identity, who is Aleph? Why did the former queen establish a marriage agreement? Why Leticia needs to find a knight.
