Yue Dai, a retired special soldier, went into hiding in the Shanghai city of the Republic of China to work as an ordinary player. He did not engage in hard-hitting espionage routines. Instead, he relied on his daily identity of repairing clocks, cooking Western food, and doing chores in the alley as a cover. He worked tacitly with the female protagonist Luan Tang, who was a bookstore proofreader, to pass on key information under the eyes of all forces, and built a secret defense line with the most inconspicuous public attitude.
