Gu Jiangzhu, an orphan from the war, was secretly trained as a "heart-piercing blade" by the survivors of the enemy country. As an embroiderer, she sneaked into the harem and approached the new emperor Zhao Chengyu, hoping to use the emperor's heart to avenge her family. But in the game with the yandere and suspicious Zhao Chengyu, she gradually fell into the love network he carefully weaved - he already knew her identity, but because of the similar trauma of being genocide in his childhood, he regarded her as "the moonlight shining into the abyss." The two went from testing each other to falling in love with each other, but when they discovered that each other was actually the enemy of the family, they fell into the ultimate sadomasochism of "can't love, can't kill". In the end, when the truth was revealed, Gu Jiangzhu used her embroidery skills to resolve the war between the two countries, and Zhao Chengyu gave her half his life in exchange for her safety.
