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.

It tells the story of the Communist Party underground worker "old ghost" breaking into the Japanese pseudo-intelligence organization, but being cut off at a critical juncture, and facing the danger of identity exposure. In a crisis, the "old ghost" dealt with the enemy and tried every means to transmit information.