In the line of duty, Detective Ma Seok-do finds himself in a heated battle with a formidable opponent, Japanese gangster Ryota Mamiya, who single-handedly takes down multiple thieves in Korea. With orders from the top to send the Japanese gangsters back to Japan, Detective Ma forms a tenuous alliance with Detective Lee, who is from Osaka, and the pair work together to apprehend the criminals despite their mutual disdain.