A boy who arrives in the US after the Shinmiyangyo expedition in 1871 returns to Korea precisely at a historical turning point and falls in love with an aristocrat.

Based in Shinmiyangyo or in the American expedition to Korea in the late nineteenth century, Mr. Sunshine tells of a Korean boy born into a family of a domestic servant fleeing aboard an American warship, later to return to his homeland American Marine officer. He ironically falls in love with the daughter of the aristocrat and discovers the dark scheme of colonizing the country he once fled.