Ace agent "Blue Bird" woke up after his death and found that he had become a son-in-law in a small town in southern Sichuan during the Republic of China. His brother-in-law blocked the door and scolded him as a waste and was worse than a dog. His father-in-law, Xiao Derong, as the head of the security team with 3,000 troops, never even looked at this useless son-in-law. Shen Yan was neither anxious nor annoyed. The first rule of the secret agent code was: the less inconspicuous the safer he was. On the surface, he was submissive, but secretly made plans. Everyone thought he was just a waste who accepted his fate. Until the secrets of the Xiao family's arms route were repeatedly leaked, and the father-in-law was furious but could not find the mole. Shen Yan happened to pass by with a cup of tea and said three words casually - that night, the mole who had been lurking for five years was caught on the spot. Xiao Derong's eyes when he looked at this good-for-nothing son-in-law completely changed. From uncovering moles to establishing an intelligence network, from training new soldiers to annexing neighboring counties, from being a despised son-in-law to a military advisor that his father-in-law can't live without, Shen Yan uses the means of an agent to make his way step by step in troubled times. Until the outbreak of the Anti-Japanese War, he led his army out of Sichuan and killed the Japanese invaders on the battlefield. His wife stood at the gate of the city waiting for his return, holding her newborn son in her arms - and all of this started from the night when the traitor was exposed. My son-in-law doesn't want to hide anymore. It's time for a change in this troubled world.
