"In 1940 Shanghai, Chen Jiaping, an underground member of the Chinese Communist Party codenamed "Mei Hua Si", is on a mission when he runs into his former fiancée Zuo Shuangtao at a critical moment when he is almost exposed. At this time, Zuo Shuangtao is already a spy of the Kuomintang military system and is looking for a way out of her predicament after a failed assassination mission. They are both unaware of each other's identities as spies and rely on the tacit understanding to cope with the Japanese's close scrutiny, and eventually pass through as a couple in a shocking manner."