Purple Butterfly

Ding Hui accidentally kills Yiling during the chaos at the train station. The resistance had arranged for an assassin to board the train, but due to a mix-up, the low-level clerk Szeto was sitting in the same car instead. When the resistance members attempted to pass materials to the supposed assassin, Szeto's confused and chaotic reaction created confusion. In the ensuing gunfight between resistance members and Japanese agents, Ding Hui's gun discharged and struck Yiling, who had rushed to meet Szeto at the station.

Earlier, the resistance's plan to use an outsider assassin already contained the seeds of this disaster, as the outsider's failure to arrive on time set the tragic chain of events in motion.

Purple Butterfly is an underground anti-Japanese resistance organization operating in 1930s Shanghai. Led by the enigmatic Xie Ming, the group operates secretly to fight Japanese occupation through espionage and targeted operations, including assassinations of Japanese intelligence officers. Ding Hui joins this group after witnessing her brother's assassination by Japanese agents, seeking revenge and solidarity against the occupation.

Itami releases Szeto because interrogation and an informant within the resistance reveal that Szeto is completely innocent, a mere bystander who was pulled into the assassination operation by pure chance. Despite being a Japanese spy hunting resistance members, Itami recognizes that Szeto knows nothing useful and poses no threat. However, this act of mercy puts Itami in a difficult position with his superiors.

Xie Ming, the leader of Purple Butterfly and Ding Hui's current lover, is killed off-screen before the final confrontation. Itami informs Ding Hui at the Japanese club that Xie Ming is already dead, which is what triggers her emotional breakdown and stabbing of Itami. The movie never shows Xie Ming's death directly, leaving the exact circumstances of his demise ambiguous.

The resistance's dangerous operations and the Japanese intelligence network's reach had been established throughout the film, making Xie Ming a vulnerable target.

Ding Hui stabs Itami in shock after he reveals two devastating pieces of information: that Yamamoto will not be coming to the club as planned, and that Xie Ming, the leader of Purple Butterfly and Ding Hui's current lover, is already dead. The combination of these revelations, losing both her revenge opportunity and the man she loves, causes her to lash out violently against the man who represents everything she hates.

Ding Hui's torn loyalties between her former lover Itami and current lover Xie Ming had been building throughout the film, making this emotional explosion inevitable.

Szeto is a low-level clerk who becomes an innocent bystander caught in the resistance's assassination plot. At the train station, due to a highly accidental mix-up, Szeto ends up sitting across from the real hired assassin in the same train car. When resistance members approach and try to pass materials about the target, Szeto's confused reaction makes them believe he is the assassin. From that moment, he becomes hunted by both the Japanese secret police and the resistance.

Despite Szeto being an innocent bystander, the resistance believes he may have betrayed them. After Szeto is captured and interrogated by the Japanese, the resistance suspects he revealed information under torture. Even when Itami releases Szeto because he knows nothing, the resistance still views him as a potential traitor who could lead the Japanese to their operations. They decide to eliminate him as a precaution.

Itami was originally a Japanese translator who lived in Manchuria with his Chinese lover Ding Hui. In 1928, he left her and returned to Tokyo. Years later, when he arrives in Shanghai, he has transformed from a translator into a Japanese intelligence operative working within the spy network. The film does not explicitly explain what happened during his time in Tokyo or what compelled him to become a spy, but his return sets up the tragic collision between his past and present loyalties.

The film opens with Itami's departure from Ding Hui in 1928, establishing the personal betrayal that would later fuel the story's emotional conflict.

Szeto shoots Itami in the ballroom after bursting in, motivated by vengeance for Yiling's death, his girlfriend whom Ding Hui accidentally killed at the train station. After shooting Itami, Szeto turns his gun toward Ding Hui, who stands beside the dying Itami. The film ends ambiguously, leaving unclear whether Szeto fires the final shot, but his thirst for revenge against everyone involved in his misfortune drives this final violent act.

The title Purple Butterfly refers to the name of the underground resistance organization that Ding Hui joins in Shanghai. The purple butterfly serves as a symbolic code name for the anti-Japanese resistance movement, representing both the fragility and the beauty of resistance fighters operating in secret. The organization uses this name to identify themselves and coordinate their operations against Japanese occupation.