Elisabeth, the daughter of a duke, was told to break off her engagement at a party by the crown prince, who had changed his mind to another daughter. She finds out that she has been unjustly confined to her prison, and that she has been betrayed by her country, to which she has given her all.
Elisabeth, who has finally reached the limit of her patience, decides to defect to her with her powerful magic book in hand! Start her new life & business in a new land. While hiding in her heart her fierce vengeance for her homeland -.

The beautiful daughter of a duke, who has been "broken off" and "imprisoned", has her strongest magic book in hand and manipulates "personal connections, economy, and military power" to defeat the traitor. ! ! ! !

https://www.cmoa.jp/title/261847/