According to the book Guoyu 國語, she was a daughter of the Lord of Shi 有施氏 (modern Tengxian 滕縣, Shandong). Once Lord Shi was attacked by the troops of King Jie, and because his country was only small and weak, he decided offer his daughter to the king. King Jie, fond of women, accepted, and from then on started to indulge in pleasures. He had made for her a wine pond (jiuchi 酒池) from which three thousand persons used to drink, when a drum was beaten. Mo Xi, who had a bad character, used to laugh at those who drowned in the pond. She also loved the sound of silk being torn apart, so that king Jie pleased her with people destroying precious silks. He obeyed her in all her frivolous wishes and brought immense suffering to the people.
Not long thereafter, Tang the Perfect 成湯 defeated Jie's armies at Mt. Lishan 歷山. The victor sent away king Jie and his beloved Mo Xi in a boat, and they are said to have died in Nanchao 南巢 in the south. Tang founded the Shang dynasty 商 (17th to 11th cent. BC).
Mo Xi's contribution to the downfall of the Xia dynasty is mentioned side by side with the efforts of Yi Yin 伊尹, who supported Tang the Perfect. Mo Xi's activities at the court of Jie are therefore also called a "female campaign" (nü rong 女戎) against the Xia.