Tensei Reijou ga Kokuou Heika ni Dekiaisareru Tatta Hitotsu no Wake: eterna

She is a countess reborn as a female knight of unparalleled power! In this life, I will protect His Majesty the King!

A "genius" female knight with no sense of awareness, who fell 17 years ago because she was unable to protect the 7-year-old third prince who was caught up in a battle for the throne. The Countess Flora, who was reincarnated with such memories of her previous life, is personally asked by the former third prince Walter, who has become the king, to be his bodyguard...? A powerful female swordsman and the king. They are both pushed around and obsessed with each other. What will happen to them in this life?