1942, Nanjing. Following a series of assassination attempts on officials of the Japanese-controlled puppet government, the Japanese spy chief gathers a group of suspects in a mansion for questioning, and eventually, torturing. A tense game of "cat and mouse" ensues as the Chinese code-breaker attempts to send out a crucial message while protecting his/her own identity. Adapted from the novel "Feng Sheng" (风声) by Mai Jia (麦家).