Bizarre murders occurred one after another in Yungang City: the victims were all brutally murdered in a confined space. The only exception at the scene was a broken mirror, with strange black stains always remaining on the fragments. Young police detective Su Yan was involved in the investigation because he was born with a strange mirror pattern ("mirror mark") on the iris of his left eye. He gradually discovered that he could glimpse the last frightening fragments of the deceased through the mirror, and even perceived the existence of the "Heart Eater" that ordinary people could not detect. At the same time, a mysterious woman Shen Qingwu, who claimed to be a descendant of the "Jianxin Sect", appeared and told him that the mirror mark was a symbol of the sect's bloodline and strength, and was also the key to resisting the erosion of Jingyuan. As the investigation deepens, a cult organization called the "Eclipse Heart Cult" emerges. They worship Jing Yuan, use ancient mirror rituals to catalyze evil thoughts in people's hearts, create chaos, and attempt to tear down the barrier between the two worlds. With the help of forensic doctor Qin Su and veteran detective Chen Zhenshan, Su Yan must cooperate with Shen Qingwu to discover the secrets of his own "mirror marks" in thrilling supernatural cases, learn to control the power of the Jianxin Sect, fight against the Heart-Eroding People who continue to pour out of the Mirror Abyss, and finally stop the Heart-Erosion Sect's crazy plan to drag the entire city into the "Mirror Abyss". This is a life-and-death struggle between reality and mirroring, at the intersection of light and darkness in the human heart.
