This person possessed memories of their past life.

The Third Prince, who, due to being the son of a concubine, was the first to be abandoned by the noble lords in the political struggle over royal succession. There was someone who reincarnated, retaining memories as the female knight who had fulfilled her duty as his guard.

She reincarnated into the same world as her previous life. What's more, she was reborn as a baby immediately after her death. This time, as the Earl's daughter — Flora Waybeia.

On her 17th birthday.

Flora was half-forced by her family to attend a party held for the selection of a bride for the Duke, His Majesty the King's nephew, and found herself heading to the royal palace. She had hoped to live an ordinary life in this incarnation, but the moment she set foot in the royal castle, her future, which might have been ordinary, became dramatically distorted.

By the obsession of her former charge, who had, unbeknownst to her, somehow ascended to become His Majesty the King.