Rainbow Eyes is a 2007 South Korean crime thriller film directed by Yang Yun-ho. The story follows a police inspector who discovers that his friend is now a serial killer. The movie was remade into a Thailand thriller named 'Cheun'.
Plot
Kyung-yoon and Eun-ju investigate a grisly murder of an affluent entrepreneur. The victim was slashed over 20 times and there's blood everywhere in his apartment. The killer was careful not to leave behind incriminating evidence, but nevertheless, a strand of the killer's hair is found. The police are then able to determine that the killer is male and has AB blood type. Kyung-Yoon's personal life is also given priority with his girlfriend asking to break up with him saying that he lives someone else and called that name when drunk. Shortly after the first grisly murder a second murder occurs. The victims seem to be unrelated but the modus operandi seems the same. When the police delve deeper into the victims’ background they discover that the two victims were stationed at the same military base many years ago. A month prior to their discharge they were transferred to another base along with a third man by the name Jong Ha. The police now believe Jong Ha could be the next victim or the killer. But their investigation has only led them to Kyung-yoon's old friend, Yoon-suh who was in the same military base and shot himself. The transfer of the trio happened after. It is revealed through a series of flashbacks that Yoon-suh was gentle and effeminate. Kyung-yoon protected Yoon-suh from bullies and it stops when he himself got into a fight and got beat up. He tells Yoon-suh to man up. Kyung-yoon independently tracks Yoon-suh. He comes into contact with Yoon-suh's old military acquaintance who reveals that Yoon-suh joined the military only because 'someone' told him to man up. From there, he was abused and raped by the trio. Kyung-Yoon goes to Jong Ha who angers him saying that Yoon-suh was passed around from bed to bed and that everyone had him. He does not apologize and instead makes light of it and laughs, which drives Kyung-Yoon mad and he gets into a scuffle with them. Later, Kyung-Yoon is seen bruised and Eun-ju calls him saying Jung Ho was found dead. Kyung Yoon is convinced that Yoon-suh got a sex change and murdered them. Kyung-yoon talks with Yoon-suh's sister, Lee Hye-Seo revealing that he thinks Yoon-suh might be the killer, though Hye-Seo says that it will never be. Eun-ju finds a secret passage in the first crime scene leading to the kitchen where she finds a cook with a weapon similar to the murder weapon. He runs, but he is apprehended. Meanwhile, the other detectives think that the singer might be Yoon-suh and questions her again. Lee-Hye Soo calls Kyung Yoon tearfully and tells him that everything was her fault. She reveals that Yoon-suh had met her and had met with the victim by coincidence and thought he might apologize. However he didn't and rather reacted violently. Printing out the identity when Yoon-suh met with the victim, Kyung-Yoon is surprised at the new identity of the killer which turns out to be his girlfriend, who he was going to marry. Kyung-Yoon confronts Yoon-suh and she tells that she kills them at which Kyung-Yoon is devastated and angry. However, he tells her to run. Both get on his bike and escape chase from police. It is slowly revealed that Kyung-Yoon was in love with Yoon-suh and that they couldn't get together because of the shame he felt. I'm the previous flashback where he beats up Yoon-suh, finally he kisses him. It was Kyung-Yoon who killed Jung Ha, as he saw a necklace with him which he had given Yoon-suh. Yoon-suh is happy that she is at last together with Kyung-Yoon. It is revealed that Eun-ja knew it was Kyung-Yoon who Jung-Ho as she retrieved his lighter from the crime scene. However, she loves Kyung-Yoon and didn't reveal it. It is also revealed that Yoon-suh didn't kill anybody, but it was the cook who killed both the rapists who had sexual relations with the singer who he confesses that he is in love with when he kills her at the end of the movie.
