Luo Xi is a top assassin in the martial world, and no saint. Through a twist of fate, she marries the emperor's own younger brother and becomes his consort. He is a prince of a great nation, immensely powerful at court and commanding a mighty army, upright, impartial, and just. Perhaps it began when he changed his tea-drinking habits because she loved pear blossom tea. Luo Xi fell helplessly in love with him. The prince was always good to her, accepting and indulging her, and showing her special favor. She gradually fell deeper, until one day she suddenly came to her senses. He regarded her as his most vulnerable rib, protecting her whenever danger arose and pushing her far from the heart of the peril. An ordinary woman would probably have been grateful and left reluctantly beneath his protective wings. Luo Xi only gave him a bleak smile and said, "I shouldn't be the prince's most vulnerable rib. I should be your right-hand woman."
With a green sword in hand, she coldly swept away his obstacles and slaughtered his enemies. In the end, she chose to divorce him and return to her hometown.