Joon is a k-pop idol, spending majority of his adolescent years training to deubt. He's happy he debuted, don't get him wrong, but he knows he missed out on a lot of teenage events, specifically his firsts. His first kiss, his first love, everything. He wasn't aware of it, but as time passed, a hole grew in his heart. The attention of paparazzi and his fans couldn't fill it, no matter how good he was, and he felt empty. (He's foul-mouthed despite being the pure one in his group.)