Lu Zheng, a detective who dropped out of school, returned to the small town and worked at a street corner steamed bun shop. He did not expect that the key evidence of the serial murder case he had been chasing for three years was hidden in the steamed buns that came out of the steamer every day - the marks on the bottom of the steamer, the fermentation time of the dough, and the number of pleats were all distress signals left by the deceased.
