Set primarily in Canton, China (now known as Guangzhou) during the Second Sino-Japanese War, the show's story follows the affairs of Chinese spies and their entanglements with underground triads and the Empire of Japan. Wayne Lai stars as special government agent Kong Sheung-hung. Co-starring is Myolie Wu as Kong's partner Cheung Kei-sang, and Edwin Siu as their rival, Chau Sai-kai.