It tells the story of Dongfang Huaizhu and Wangquan Hongye, the leaders of two prominent families, the Dongfangs and the Wangquans. In an era when humans and demons are at war, they join forces to stabilise the situation and revive the Alliance of Unity. On the seventh day of the seventh month, at the Bamboo Pavilion on the River Huai, their fates become intertwined like the scabbards of two swords, never to be parted. They make the most moving of promises and tell a story that has endured for generations.