The film is set in Seoul, 1945, during the final days of Japanese rule. Kanemura is a well-connected con artist who makes money by selling ancient Korean artefacts to wealthy Japanese collectors. His eyes are set on Haruko, a beautiful jazz singer in a downtown nightclub; unbeknownst to anyone, Haruko has been moonlighting as "Haedanghwa" ("Rugosa Rose"), a masked cat burglar who has carried out a succession of high profile thefts. She is also pursued by Yamada, a colonel in the Japanese military police, who is jealous of Kanemuras affections towards her. The owner of the nightclub and his chef, Hee-bong, secretly work for the Korean independence movement. After a twenty year search, the Japanese Chief of Statea high-ranking official in Koreahas recovered the "Light of the East", a 3,000 carats (600 g) diamond and lost treasure from the ancient kingdom of Silla. Receiving orders to send the diamond to Japan, a lavish send-off party is arranged. Kanemura attends the event with Haruko; he plans to steal the diamond, but she has the same idea, and both are surprised to see the other when they get to the safe where it is kept. After a brief struggle, it is Haruko who makes her escape with the diamond, leaving Kanemura to face the authorities. But the nightclub owner and his chef are also at the party, and their bungled assassination attempt on the Chief of State results in a fire, allowing Kanemura to slip away in the confusion. Yamada is given the task of retrieving the diamond, much to the chagrin of Suzimura, the chief of police, who feels that he has jurisdiction. Hasekawa, a police inspector, immediately suspects Haruko, but Yamada wont hear of it, blinded by his feelings for her. Meanwhile, Kanemura manages to track down Haruko, finding her on a train to Soviet Russia disguised as a geisha. She refuses to hand over the diamond, but he has planted explosives on the railway track, and, having cut off her escape route, succeeds in dragging her back to Seoul. Unable to discover the diamonds whereabouts, Yamada rounds up 100 Korean civilians and orders them to be executed if it is not returned. Kanemura is also unsuccessful in getting Haruko to give up the diamond, so he allows her to slip away and then secretly follows her. She leads him to a local pawn shop, but her accomplice Jang-cheon is really an agent of the Korean independence movement, and when Kanemura reveals himself as the leader of the Korean secret intelligence, the two men turn against her. Disguised in Japanese military uniforms and with the diamond now in their possession, they are about to make their getaway when Hasekawa arrives on the scene and holds them at gunpoint. Suzimura and his other police officers soon follow, but he misreads the situation; believing Hasekawa to be a traitor who has taken Japanese soldiers captive, he orders his men to shoot him. This allows Kanemura and Jang-cheon to escape through a hidden tunnel, but Haruko is captured. Jang-cheon thinks that he has the diamond, but Kanemura has switched it, and, feigning injury, he tells Jang-cheon to go on without him; he does, but is soon after arrested and thrown in with the other hostages. Now on his own, Kanemura negotiates a deal with the Chief of State: he will return the diamond in exchange for Haruko and ten crates of gold. Yamada is sent to make the exchange, but the Chief is stopped by the chef and nightclub owner, who are trying to make good on their assassination attempt. The two independence fighters are injured in a shootout with Japanese soldiers, but succeed in their objective, blowing up the Chiefs car. Yamada makes the exchange with Kamemura, but attempts to double cross him, and the two men fight. The diamond is broken, and Kanemura manages to escape with Haruko and the gold. He later reveals that the diamond was in fact a fake, and that he manipulated the whole event to secure gold from the Japanese for the purposes of rebuilding Korea. Back in Seoul, the execution of civilians is halted by the radio broadcast announcing the surrender of Japan.