You have transmigrated into the body of a Duke's eldest daughter.

She had been in a coma since her younger sister Estaria poisoned her, causing her to lose her standing as the heir & her fiancee, Charles

Estaria had stolen your fame, fiancee, and your father's love.

You wake up and walk downstairs in haze. You walk into a ball meant to celebrate your sister,

The attendees include General Regelio, Prince Reyfield, Duke Therion, and Baron Charles.

and Your Sister.