During the isolation period in Shanghai in 1941, undercurrents surged. Shen Yanzhi, the "Intelligence Specialist" who returned from Japan, lurks as the chief of the Third Section of the Shanghai Intelligence Department of Wang Puppet, but his true identity is "Han Xing", an agent of our "Spark" underground organization.
He walks between the ambitious Wang puppet colleagues and the ruthless Japanese military super high school section chief Hideki Sato. He must not only deal with Zhou Mingyuan's suspicion and temptation, but also decipher the secrets of the Japanese army's "Qingxiang" plan; he must take risks to rescue the arrested comrade Lao Wu and the American journalist John, and he must unite dock workers and guerrillas to blow up the Japanese "Sakura" arms cargo ship and intercept the transport team that plunders China's wealth.
The bookstore owner Su Manqing is his most trusted traffic officer. The microfilm in the pen, the secret message in the spine of the book, and the code on the window connect the lifeline of intelligence in the darkness. The sacrifice of his comrade "Fisherman", the betrayal of the mole Li Mo, and Sato's crazy revenge make every action like walking a tightrope.
From the alleys of the French Concession to the mountains and forests of Qingpu, from the interrogation rooms of the Special High School to the cave dwellings of Yan'an, Shen Yanzhi spread light in the hearts of the enemy under the name "Han Xing". He hid the gunshot wound in his arm, swallowed the grief of the sacrifice of his comrades, fought against the invaders with wisdom and courage, and practiced the belief that "no matter how small the cold star is, it can illuminate the dark night; no matter how small the spark is, it can ignite the wilderness" - just to wait until the day when the mountains and rivers are safe and Shanghai is full of light.
