Luhan is an 18 year old boy who lives with his mother in Busan. His father dies in a car accident when he was 4 when they lived in China, so his mother decided to move to South Korea to forget about the past. Luhan fell in love at first sight with Sehun, he meets Sehun right after falling off of his bike, when he helps Luhan up. Sehun is there on vacation, but he soon returns to his hometown, Seoul. Every second, every minute of everyday, Luhan would always think and dream about him. Wanting to find a new job, Luhan's mother decides that they should move to Seoul, where Luhan would be attending SM School of Arts. Luhan thought that it would be hard being a new student at a new school, until his first day of school there, his first period class, he saw him, Sehun. Luhan makes new friends, Lay, his best friend, Baekhyun, Kyungsoo, Xiumin and Tao.  He finds out that Sehun is gay, which makes him happy but then finds out that a boy named Kai, likes him too, so both of them start being rivals. How will school be to Luhan with his rival, Kai? Will Sehun remember Luhan when they met in Busan?