Lin Chen wakes up in a death row prison in Laohujiqiao Prison in June 1937. He is a time traveler who now occupies the body of an assassin from the Iron Blood Extermination Squad, captured after a failed assassination attempt on Dai Chunfeng, director of the Fuxing Society Secret Service. The cell reeks, and the food slot offers a last meal of roast duck and meat broth. Lin Chen notices eight simplified Chinese characters carved on the wall, written in his own handwriting, though he has no memory of doing so. He scrapes them off to avoid future trouble. The prison guards arrive with forged documents claiming he is to be executed, but Lin Chen senses a test. They hood him, remove his restraints, and lead him to a special room painted with black and white spiral patterns designed to induce psychological stress. Lin Chen understands that not resisting means accepting the test. He stares straight ahead, spacing out to neutralize the psychological suggestion, impressing the observers.Back at the Secret Service headquarters, Dai Chunfeng is under immense pressure. The Japanese army’s military exercises in North China have alarmed the National Government. A swift military operation to block Japanese ships in the Yangtze River is leaked, causing the ships to flee downriver. The old man is furious, and Dai Chunfeng is severely scolded. The Party Affairs Investigation Bureau captures the traitor Wang Ling and his son, but the Japanese spy escapes. Further investigation points to Song Weixin, a deputy battalion commander with falsified records, who is romantically involved with the daughter of Deputy Director Zhou of the General Staff Headquarters, a confidential secretary in the Cipher Room. Song cannot be arrested without solid evidence due to his connections. At this moment, the Iron Blood Extermination Squad’s assassination attempt brings Lin Chen to Dai Chunfeng’s attention because Lin Chen bears an uncanny resemblance to Song Weixin. Dai Chunfeng conceives Operation Wildcat: to train Lin Chen to replace Song Weixin, infiltrate his life, and uncover the spy network. He orders Chief Secretary Zhang Pucheng to take charge. Lin Chen is to be tested and integrated into a team over one month, after which he will replace Song Weixin. Any abnormalities will be dealt with immediately.The team consists of Qi Tai from the Intelligence Team, Zhao Jiu from the Action Team, and Li Yuanzhou from the Telecommunications Team, posing as prison guards. They witness Lin Chen’s psychological test and recognize his unusual endurance. Zhang Pucheng reports to Dai Chunfeng, who decides to proceed with the operation. Zhang returns to the team with a sealed folder, announcing the secret order from the boss. The three team members discuss their mission, realizing they are being formed as a field infiltration team destined for dangerous work in Japanese-occupied territory. Lin Chen, unaware of the full plan, remains calm and cooperative, understanding that his survival depends on passing the tests. The operation is to be kept secret from the Military Affairs Office to prevent leaks, with Dai Chunfeng emphasizing that no word of Operation Wildcat must escape. Lin Chen’s past as an Iron Blood Extermination Squad assassin, his unusual knowledge of simplified characters, and his ability to withstand psychological pressure make him a viable candidate. The story sets up Lin Chen’s transformation into a spy, the looming conflict with Japanese espionage, and the internal political struggles within the National Government. Lin Chen’s goal becomes survival and completion of the infiltration mission, while Dai Chunfeng seeks to redeem himself and catch the Japanese spies. The plot ends with the initiation of the training phase, as Zhang Pucheng and the team prepare to execute the first steps of Operation Wildcat.