Love Song for Illusion S01E01 - The Other One and the Last One

Sajo Hyun, the Crown Prince harbouring an alter ego, encounters a woman in the fabric shop. She is Yeon Wol, the lone survivor of the Yeon family annihilated a decade ago. Driven by a vow to avenge her parents' demise, Yeon Wol now stands poised with a knife aimed at the King's throat, marking the imminent fulfilment of her pledge.