When Lin Yu, a modern junior high school student, visited the Songhu Battle Memorial Hall, he accidentally triggered a mysterious pocket watch and traveled to Shanghai on the eve of the Songhu Battle in 1937, becoming the son of underground party member Lin Yuanshan. In this turbulent era, Lin Yu relied on modern knowledge and courage to fight side by side with his father, underground party members, and patriots.
He experienced the first confrontation with the Japanese invaders and successfully cracked the cipher machine to obtain important intelligence; he sneaked in the dark night to avoid being pursued by the Japanese army and delivered intelligence; he also participated in fierce battles and destroyed the Japanese army's communication lines and ammunition depots. In the tests of life and death, Lin Yu gradually grew into a staunch anti-Japanese warrior and launched a thrilling contest with the enemy.
