This is one of the most tragic dramas I have seen. I felt really sorry for Lee Jang-il character.
Lee Jang-il was smart. He was number one student in school and wanted to be a prosecutor in the future. However, after the death of his mother, his father gambled and was in debt. Debt collectors came to his class during the exam and dragged him out. A classmate, Kim Sun-woo, chased those men away. The two boys became good friends.
The debt problem made Lee Jang-il a cold, lonely person. Kim Sun-woo was his only friend. Kim Sun-woo protected him from debt collectors and in exchange, Lee Jang-il tutored him.
Lee Jang-il's father, Lee Yong-bae, was a simple man. He didn't gamble anymore, but worked in a villa construction belonged to Mr. Jin, a rich businessman.
Kim Sun-woo's father, Kim Kyung-pil, was not Kim Sun-woo's biological father. Kim Kyung-pil was dying because of an illness and planned to give Kim Sun-woo to his real father, Mr. Jin. The two men fought, witnessed by Lee Yong-bae. Mr Jin thought that Kim Kyung-pil had been dead and asked Lee Yong-bae to get rid of the body, and in turn he would pay for Lee Jang-il's study.
But Kim Kyung-pil had not been dead yet. Lee Yong-bae could have called for an ambulance if he wanted. But he didn't.
Kim Sun-woo didn't believe that his (adoptive) father committed suicide - as it had been staged by Lee Yong-bae. He planned to send a petition to the police. At first, his best friend Lee Jang-il promised to help him, but after Lee Jang-il found out that his own father and the man who would pay for his study involved in the murder, he prevented Kim Sun-woo to send the petition. He hit his head with a log of wood and threw his body to the sea.
The scene where Lee Jang-il had to kill his only friend was hauntingly sad. He hit his friend's head from the back three times. Why he didn't stop after the first hit? Was he so ambitious and desperate to continue his study? Didn't Kim Sun-woo promise him to play for his study in Seoul? Without Mr Jin's help, he could still go to a university in Seoul. He and Kim Sun-woo might have to work hard, but at least they would have a piece of mind.
Lee Jang-il never forgot what had happened. He became lonelier and colder. He never smiled happily and lived with his guilt.
Kim Sun-woo didn't die from the attack, but he became blind. His late mother's friend came to send him overseas, to treat his eyes so he could see again, then sent him to study and work in mining industry. When Kim Sun-woo returned to South Korea 15 years later (after the attack), he was a successful business man and ready for his revenge against Lee Jang-il and his father and Mr Jin. Slowly he destroyed the life and career of the man who once was his best friend.
Another favourite character of mine is Choi Su-mi, a painter. She met Lee Jang-il in high school and always liked him. When they first met, Lee Jang-il thought she was a daughter of a rich man and wanted to befriend her. However she was not. Her father was a shaman and this made Lee Jang-il looked down on her. Choi Su-mi witnessed the tragedy when Lee Jang-il attacked his best friend, but she didn't do anything. [Later she became Kim Sun-woo's target for revenge, too.] In her pathetic way to keep Lee Jang-il in her hand, she documented the tragedy in a series of paintings.
Money was important to Lee Jang-il because of his experience with the debt collectors, but he didn't go for rich girlfriends. The one he truly loved was Han Ji-won, who didn't have a lot of money. But Han Ji-won didn't love him.
Choi Su-mi witnessed the tragedy between the two boys and her father witnessed the tragedy between the boys' fathers. Like her, he also didn't do anything to prevent the murder.
Kim Sun-woo's girlfriend, Han Ji-won, persuaded him to stop. Kim Sun-woo told her that he would stop if Lee Jang-il apologized. But the two once-best-friends were proud.
Only in the end after he had been completely destroyed, Lee Jang-il apologized. He and Kim Sun-woo returned to the place where he attacked him 15 years ago, with a hope that he could overcome the nightmares. But the nightmares never stopped.
Mr Jin didn't need to kill Kim Kyung-pil from the start. He was not a politician so he didn't need to hide the fact that he had a son out of wedlock. It was okay and he was rich enough to adopt Kim Sun-woo. His wife didn't care, anyway.
Murder was not easy, but the hardest part was to get rid of the dead body. In the scene where Lee Jang-il watched movies with Han Ji-won, one of the movies they saw was Plein Soleil. Perhaps it was where the scriptwriter got the idea of how difficult it was to get rid of dead bodies.
The cast was quite interesting. The young Lee Jang-il was played by Im Si-wan (25 years old) and young Kim Sun-woo by Lee Hyun-woo (20 years old), and the adult Lee Jang-il by Lee Joon-hyuk (29 years old) and adult Kim Sun-woo by Uhn Tae-woong (39 years old). Note that adult Lee Jang-il only 4 years older than the young.