Amy (you) is a Korean-American girl. Was a bestfriend with Yesung since the age of 5. But he had to move to Korea due to his father's job. 13 years later, you moved to Korea too and didn't remember anything about Yesung. The only thing you know that you gave your bestfriend a necklace with a sneakers-shaped with it. Fortunenately, you entered the same school as Yesung but you still doesn't remember about him. Until one little thing can change everything..