On the eve of the Songhu Battle in 1937, Song Shiyu, the illegitimate son of the Song family of the four major families, lurked in Shanghai as a lieutenant colonel of the military command. On the surface, he looked like a cynical playboy, but in fact he was an underground member of the Chinese Communist Party. After reuniting, he and Shen Yao (a CCP agent) launched a two-pronged espionage war: not only to steal the core intelligence of the Kuomintang, but also to prevent the family's arms trade with Japan. Amid the suspicion of the military commander, the secret fight between the family, and the pursuit of the Japanese army, the two used the code names of "Spring Silkworm" and "Jingzhe" to convey information with Kunqu opera lyrics, and composed a tragic epic of faith and love intertwined on the bloody beach.
