Description："Key Person" is a comedy film directed by Park Chung-gu. The film tells the story of a new honest and upright chief who is determined to build his own clean political life and overcomes various difficulties to fight corruption after taking office. In addition, it will also show his daily life as a father in private. Yoon Jin-seo plays the role of "Ha Young", an assistant appointed by the new chief. In the film, she is a passionate new generation elite assistant. During working hours, she is definitely a hard-working and enthusiastic civil servant. However, after get off work, she becomes a leftover woman wandering on the road to happiness. She is a very cute and bright character.