In a penthouse apartment on a rainy night, a well-known designer died in a locked study, with a bronze dagger stuck in his chest and an upside-down pendulum symbol drawn with blood beside him, marking the beginning of a secret room murder. Major case captain Lu Chen insists on the supremacy of evidence, while Su Wan, a doctor of criminal psychology, believes in psychological profiling. The two polar partners are at odds with each other due to conflicting ideas, but during the investigation they discover that the case is far from an accident. From the hasty silence of business partners, to the dusty past of the fire in the orphanage, to the serial murders that spanned three years, the pendulum symbol follows him everywhere. This is not only a cat-and-mouse game, but also a crazy provocation by a criminal organization. When the truth is revealed layer by layer, Lu Chen and Su Wan must not only decipher the secrets behind the symbols, but also face the shadows of the past. In the game of life and death, let the pendulum of justice finally stop on the side of the truth.
