The story of a 34-year-old woman who's saddled with family debt and only has a high school qualifications, but dreams of becoming a fashion designer. Her youthful appearance is her only advantage; she is mistaken for a 25-year-old university graduate and subsequently lands her dream job when she's hired by a fashion design company.
Ha-neul (Jang Na-Ra) is a gifted violonist who stays at home mostly. Bada ([[Juni (actress)|Juni) was abandoned by her parents. Jin-kyu (Yu Ah-In) lost his parents at an early age and now delivers pizza. Through music, friendship, and love these three friends will learn lessons on life.
Jang Na Ra and Park Jung Chul add a new and unconventional page to the modern fairy tale in the romantic comedy Oh! Happy Day. Jang Na Ra stars as Hee Ji, a hot-tempered girl with a strong sense of justice. She bursts into a club to stand up for her friends who were rejected from a singles party, and she ends up meeting Kim Hyun Jin, whom she marks as her Prince Charming. Being the determined young woman that she is, Hee Ji breaks into his hotel room the next day and steals his schedule. Seeing Hee Ji everywhere he goes, Hyun Jin gradually develops feelings for this cheerful girl who seems to match him so well. Things seem to go just fine until this carefully planned "fate" is finally revealed.
Jang Na Ra plays a cute and innocent country girl who often daydreams of rescuing her prince. One day, she meets Jang Hyuk who accidentally falls into her bath tub while she was taking her bath. Not off to a good start they started arguing over the matter. However, the story goes on to tell how Jang Nara arrives in the big city due to her plan to settle her irresponsible parents' debts. She moves into Jang Hyuk's house as a hired servant hence begins to teach the rich spoiled brat (Jang Hyuk) some manners through her down to earth scoldings and no-nonsense attitude. This drama gets totally hilarious in many scenes where Jang Nara and Jang Hyuk's combination comes out as refreshingly cute. Jang Hyuk plays a rich and proud man who inherits his father's business but is later betrayed by his own cousin and uncle leading to his downfall. On the other hand, Jang Nara plays a girl that he meets who help him pick up the pieces in his life, from defeat to success. A very well written drama with a story many will enjoy!