In the romantic-comedy "Boku to Star No 99 Nichi", top Korean actress Han Yoo Na falls in love with a quiet man named Kohei Namiki. Kohei Namiki is a single man approaching his 40's. He works part-time at a security company. He has a sweet and handsome appearance which some people take advantage of as he is easily swayed by those around him. Kohei often takes care of his sister's three kids because his sister has a habit of wandering around. He is a passionate man and dreams of finding his star, but 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. Even though she has a near perfect appearance and style, she prefers to act like a normal person. She enjoys eating simple Japanese foods, and on the filming set, Yoo Na goes out of her way to help others. Yoo Na has a pure and kind spirit and seems to be the envy of all. Inside, however, Yoo Na is lonely working in the entertainment field and she 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 ninety-nine days, their relationship changes. But on the hundredth day when the contract ends, what choice will they make?
33-year old Han Je In is a mystery novelist who is notorious for habitual false reporting to the police in town. Her only friend is police officer Rok Hwan, who has had a crush on her since childhood. One day, Je In hears a scream of help from an apartment upstairs and reports that a serial killer lives above her but no one believes her. Convinced that Jason, the handsome man living upstairs, is a serial killer, she asks Rok Hwan to help follow him around with her. But as she learns more about Jason in her pursuit to uncover the truth, she begins to fall for him. Seeing her in this state, Rok Hwan feels a tinge of jealousy.
