Zhang Xiaofan (Li Yifeng), and childhood friend Lin Jingyu (Cheng Yi), are the sole survivors of a village massacre. The two are accepted into the Qing Yun sect, where they learn the ways of the Immortal Sword. Although he is hardworking and determined, Xiaofan struggles to catch up to his peers due to his slow wit. One day, he acquires a “dementor sword” by chance when he was training in the mountains.
During the martial arts competition held within Qing Yun sect, Xiaofan enters the Top 4. Together with Lu Xueqi (Yang Zi), Lin Jingyu and Zeng Shushu (Qin Junjie), he heads to the Bat Cave in Mt Kongsan to investigate the trails of the demonic sect. There, Xiaofan encounters danger and pivotal circumstances make him grow and mature. Along the journey, he meets Bi Yao (Zhao Liying), daughter of the Ghost King. Their relationship slowly grows and takes a meaningful turn through these difficult times.
However, the villainous Ghost King attempts to overthrow the Qing Yun sect, and Xiaofan puts his life on the line. Bi Yao sacrifices herself to save him, falling into an endless sleep.