Chang Ping'an, a top student at the Exorcist Academy, suddenly transformed into a demon and attacked others during graduation, leading to him being labeled a half-demon and hunted down. While on the run, he sought a way to purge his demonic nature and arrived at Helltown of Heaven, where he became entangled with the female demon, Hong Dian. Eventually, he discovered that he was human all along and had been used by Master Yin to awaken the vengeful spirit of the "Demon Ape," the lingering resentment of the Demon King Sun Wukong. As the Demon Ape wreaked havoc in Helltown of Heaven, Ping'an ultimately joined forces with fellow exorcists to subdue it, protecting the people in the process.