The story follows Feng Yu Ji, a woman living under an assumed name, who returns to the Shen household under the guise of her twin sister, the young mistress of the Shen family, to seek revenge for her sister. She gets close to Shen Tan Qian, the son of a wealthy merchant, and begins investigating the truth behind a long-buried murder case, ultimately revealing the true culprit and ensuring they face justice. Throughout this journey, Feng Yu Ji and Shen Tan Qian move from mutual distrust to open honesty, and eventually, they heal each other. With courage, wisdom, and the power of their sacrificial love, they bring the truth to light. As the truth unfolds, their combined efforts also eradicate the Shen family's opium trade with the Japanese, gradually ending the city's opium addiction and establishing a new era of science and civilization.