Xiao Song is taken as a trader and Bai Yi asks Ran Yan for help finding him. Ran Yan agrees to help since Bai Yi pays her. Ran Yan sneaks into the brothel to find Xiao Song and poses as a musician. The real Master Six shows up and confronts Xiao Song. They test them to see who can determine who took opium. They then test them with fake officials storming the place. Xiao Song finds the real killer and his motive for killing. (Source: jindreame at MyDramaList)