- Lin Man (Lin Chuyao) (female protagonist): A popular singer in Paramount, she uses her performances to convey information and secretly rescue arrested comrades.
- Gu Yu (male protagonist): A senior executive of HSBC Bank, who used financial transactions to cover the assassination mission of the military commander.
- The trigger of the conflict: Sato, a senior Japanese military officer, was assassinated, the underground party's joint points were exposed, and both of them were suspected of leaking secrets at the same time.
- Gu Yu was ordered to approach Lin Man to investigate clues about the Communist Party. Lin Man deliberately seduced him to obtain the military command code.
- Classic scene: Dagger confrontation backstage at Paramount → Waltz game on the dance floor → Rainy night on the Bund
