She transmigrates as a villainous cannon-fodder girl and is bound by the System from the start, tasked with winning over the violent villainous crown prince!
The original girl threw herself at him and died miserably. She turns the tables and takes the mad crown prince in hand, treating his illness with silver needles, commanding the room with her fists, and serving up face-slapping and revenge all in one!
“Crown Prince, behave, or I'll beat you up~”
Later, the once-violent crown prince holds her close, eyes red-rimmed. “Your Highness, don't leave me. I'll give you my life.”