Wang Jiazhi (Tang Wei), who was originally a student at Lingnan University, went to Hong Kong to study because of the war. She joined the drama group organized by the patriotic youth Kuang Yumin (Wang Leehom) at the University of Hong Kong. The patriotic drama they starred in aroused their patriotic sentiments. When Kuang Yumin learned that Mr. Yi (Tony Leung), the spy chief of the Wang Puppet Government, was in Hong Kong, they conspired to assassinate Mr. Yi. Wang Jiazhi, who used the alias "Mrs. Mai", quickly gained the trust and love of Mrs. Yi (Chen Chong), and the beautiful "Mrs. Mai" also attracted Mr. Yi's attention. Just when things were in full swing, Mr. Yi suddenly wanted to return to Shanghai. Since then, Wang Jiazhi has been living in Shanghai, but she didn't expect to meet Kuang Yumin again. When she learned that the assassination was not over, Wang Jiazhi became a spy again and appeared in front of Mr. Yi as "Mrs. Mai" again. After the reunion, the relationship between the two developed further. At this time, Mr. Yi had no taboos about Wang Jiazhi because he fell in love with her, and Wang Jiazhi's heart became ups and downs. The assassination was going smoothly, but when Mr. Yi gave Wang Jiazhi a dazzling diamond ring to express his love, Wang Jiazhi made a surprising decision...