In the romantic-comedy "Boku to Star no 99 Nichi" top Korean actress Han Yoo-Na (Kim Tae-Hee) falls in love with a quite man named Kohei Namiki (Hidetoshi Nishijima).
Kohei Namiki (Hidetoshi Nishijima) is a single man approaching his 40's. He works at security company as a part-time job. He also has a sweet and handsome appearance, which some people take advantage of. Kohei is easily swayed by those around him. Kohei often read moretakes care of his sister's three kids because Kohei's sister has a habit of wandering around, but he is a passionate man and dreams of finding his star. Because of his family and economic situations, Kohei can't follow through on those dreams.
One day, Kohei is assigned security detail for the beautiful actress Han Yoo-Na (Kim Tae-Hee). Even though she has a near perfect appearance and style, she prefers to act like other normal people. She enjoys eating simple Japanese foods and on the filming set Yoo-Na will stop to help others. Yoo-Na has a pure and kind spirit. She seems to be the envy of all, but inside Yoo-Na is lonely working in the entertainment field and she also has a big secret.
At first, bodyguard Kohei and top star Yoo-Na don't get along. With time they become closer. Over the next 99 days their relationship changes. On the 100th day when the contract ends what choice will they make?
Kim's role will require her to speak Japanese lines for the first time.