Lee Sungyeol is a famous idol in a group called Infinite. He may seem cheerful and happy on the outside, but he is very insecure inside because of an incident long ago. s don't speak of it outside of the dorm, because he had asked them not to and it would hurt the group's reputation. Every single day, he suffers through life. He thinks he is alone, but he has a great friend beside him the entire time, Kim Myungsoo. Myungsoo is very close with Sungyeol, but still doesn't know everything his best friend is hiding. Myungsoo will do anything for his best friend and watching Sungyeol hurt himself aggravating. He wanted to know what had truly happened, but Sungyeol is unwilling to open up. Will Myungsoo be able to break Sungyeol's shell and save him? Or will he have to watch his friend fall deeper into the abyss.