Yeon-du asks her best friend Bora to collect all the information she can about Baek Hyun-jin while she is away in the U.S. for heart surgery. Bora decides to get close to Baek's best friend, Pung Woon-ho first. However, Bora's clumsy plan unfolds in an unexpected direction. In 1999, a year before the new century, Bora, who turns seventeen, falls into the fever of first love.