Two identical twins, Han Soo Ho and Han Kang Ho, look exactly alike but lead entirely different lives. Han Soo Ho is a respectable judge who does everything by the book, while Han Kang Ho is not only a convicted criminal but a repeat offender. When Han Soo Ho suddenly disappears, Han Kang Ho ends up taking his brother’s place and living a new life as a judge.
Mr. Sunshine centers on a young boy born into a house servant's family and travels to the United States during the 1871 Shinmiyangyo (U.S. expedition to Korea). He returns to his homeland later as a U.S. marine officer. He meets and falls in love with an aristocrat’s daughter. At the same time, he discovers a plot by foreign forces to colonize Korea.