I'm gonna give all my secrets away

Mark is popular. He's a wild beast in parties, he dated a lot of people at his school. And there he is, returning from North America after four years.

Haechan is different. He's cold, never been in a real relationship due to some personal stuff. And there he is, watching sideways, as the Mark Lee in the center of the hallway, his friend bys his sides.

Renjun is okay. He was near depression last year, he spent his summer in China at his parents' friends. And there he is, at the back of the class, eyes open wide as if he saw a ghost.

Chenle is sick. He keeps people out of his life, avoiding sadness and endless goodbyes when he'll leave. And there he is, entering the school of the guy who stayed at his house during summer.