Marine Boy () is a 2009 South Korean film. The feature film debut of writer and director Yoon Jong-seok, it stars Kim Kang-woo, Cho Jae-hyun and Park Si-yeon in the lead roles. Marine Boy is the story of a former national swimmer who finds himself in debt, and out of desperation is employed as a mule by a gangster boss, smuggling drugs by sea. Yoon regarded the film's title as a unique point, saying, "There is something beguiling about its duality, how these criminals are called something that romantically calls to mind the popular cartoon Marine Boy or the star swimmer Park Tae-Hwan". Plot Former national swimmer Cheon-soo dreams of travelling to Palau, and to fund his trip he works as a swimming instructor by day while gambling at night. However, after losing a game of poker he finds himself heavily in debt and in trouble with the loan sharks. Kang, the head of a local drugs syndicate, offers to pay off Cheon-soo's debts; in return, Cheon-soo must work as a "marine boy", a mule who smuggles drugs across the open waters. Knowing the danger he faces, Cheon-soo tries to make a run for it, but he is arrested at the airport by police detective Kim Gae-ko. Kim is intent on capturing Kang, and faced with no other choice, Cheon-soo agrees to work as a spy on his behalf. His situation becomes further complicated when he falls for Yu-ri, a jazz singer under Kang's charge and the daughter of Kang's best friend. But Yu-ri suspects Kang of killing her father, and she and Cheon-soo plot to take the drug money for themselves. Cast Kim Kang-woo ... Cheon-soo Cho Jae-hyun ... Company president Kang Park Si-yeon ... Yu-ri Lee Won-jong ... Detective Kim Gae-ko Um Hyo-sup ... Section chief Jo Oh Dae-hwan ... Coach Lee Choi Su-rin as Jazz bar owner Yoo Ji-yeon ... House madame Park Byung-eun ... Ji-ho Im Hyeong-gook ... Choi Do-wook Jo Jae-yoon ... Department head Im Kim Joon-bae ... Company president Hwang Oh Kwang-rok ... Doctor Park Choi Jung-woo ... Gambling man Hakuryu ... Suzuki Production Marine Boy was the debut feature film by writer and director Yoon Jong-seok. Yoon said that he first began thinking about the story after watching a "very moving film noir", which inspired the type of characters he would later write into his script. During casting he was keen to avoid