Gu Xueqing accidentally enters a closed sanatorium, and relying on keen observation, psychological analysis, and meticulous reasoning, she gradually sees through patient abnormalities, hospital cover-ups, and a series of bizarre cases. Through live streaming, she shares the investigation process, helping victims find evidence and restore the truth. During the investigation, she meets the cold and decisive Shen Muyuan. Together, they progress from mutual testing to side-by-side cooperation, tracking down missing person cases, theft cases, and village secrets, uncovering Gu Xueqing's identity amidst layers of crises and behind-the-scenes conspiracies, and guarding the ultimate justice.