"Mary Stayed Out All Night" is a South Korean romantic comedy television series that aired in 2010. The story revolves around Mary, a free-spirited young woman who finds herself in a complicated love triangle involving two men: Kang Mu-gyul, a laid-back musician, and Lee Seon-joon, a serious and ambitious heir. The series explores themes of love, identity, and the challenges of adulthood. As Mary navigates her relationships and personal growth, viewers are treated to a mix of humor and heartfelt moments, making it a charming addition to the romantic comedy genre.