Zutaboro Reijou wa Ane no Moto Konyakusha ni Dekiai sareru

Marie, the second daughter of the impoverished Shaderan family, is treated like a servant while her parents pour all their attention into her beautiful older sister Anastasia. On Marie's birthday, she meets Count Kyros Granado, who is immediately drawn to her and to her knowledge of his culture. A misunderstanding, however, leaves him believing the woman he met was Anastasia, and his marriage proposal is sent to the wrong sister.

When Anastasia dies in an accident on the way to the marriage, the family forces Marie to take her place. Marie expects to be an unwanted substitute, only for Kyros to realize that she is the woman he wanted from the beginning. Faced with a kindness she has never learned how to accept, Marie begins a harder journey than entering noble society: believing that she deserves respect and love without becoming anyone else's replacement.