Behind the palace walls, a sharp-edged second princess secretly makes poison as medicine. Outside, an assassin, carrying the blood debt of his family's massacre, hides his identity and searches for his lost sister. At a royal banquet, a masked old acquaintance returns—but the tattoo on his back is gone. Is he the mountain boy she knew six years ago? Is she the sister he's been searching for? A jade pendant and a tattoo point to a deadly conspiracy. Power struggles, mistaken identities, and a blood-soaked past lead to a final counterattack. The princess and the boy, from missed recognition to true partnership, fight their way to redemption—caught between betrayal and love.
