In 1999, a teen with a heart of gold begins keeping close tabs on a popular classmate as a favor to her smitten best friend.

Follows the first love and friendships of a high school student. Bo-Ra is 17-year-old high school student. She is good at taekwondo and has a bright and positive personality. She is also a member of the broadcasting club at her school. Woon-Ho is a member of the same broadcasting club. Bo-Ra is best friends with Yeon-Du , who attends the same school. Yeon-Du has a crush on Hyun-Jin. She asks Bo-Ra to find out everything about Hyun-Jin and goes to the U.S. to have heart surgery. After that, Bo-Ra begins to observe Hyun-Jin closely and he falls in love with her.