Lin Shen, the great-grandson of Lin Qiubai, a famous detective in the Republic of China, inherited his grandfather's old notebook and gained his great-grandfather's complete detective memory and reasoning abilities. As a private detective, he relies on his "memory regression" skills to crack unsolvable murder cases such as secret room murders, serial killers, and perfect alibi. Partnering with war reporter Su Wan, he gradually discovers that all cases point to a transnational criminal organization, the "Darknet Arbiter." In the process, Lin Shen reconstructed the unsolved "Cheongsam Killer" case during the Republic of China through the memory fragments of his great-grandfather, revealed the historical origins of the "Darknet Arbiter", and finally destroyed the organization, completing family inheritance and self-salvation.
