Classroom 1, Grade 4, Baekwoon Elementary School. Today, Younghoon is in an eraser-eating contest with Kangsan. Despite his hard practice, Younghoon loses the eraser to Kangsan’s stubbornness. While Younghoon searches every corner of the house for the eraser, his older sister gives him a blue eraser. With a glimmer of hope, he tries to compete again, but Kangsan takes that eraser away from him through a dirty trick. When Younghoon returns home in a miserable state, all that awaits him is a house in ruins and his older sister’s empty room. Younghoon continues to train hard today, hoping that if he wins the eraser-eating contest, his older sister will come back.