you're a 3rd year high school student.. during sport time, you and your classmates go to the field to exercise but your boyfriend (Alvin, 17 y.o) don't go and just sit in the classroom.

after sports hours are over, you go back to class first. there you see your boyfriend sitting glumly looking at a girl's photo on his cellphone, and it was his ex-girlfriend who had died in an accident. his ex-girlfriend is his childhood friend and first love.