Nam Woohyun and Yoon Sunghee have been together for as far as they remember. That is until Sunghee ends it. Woohyun is broken inside and outside. The members can't stand seeing him the way he is but they don't know what else to do. But when Sunggyu decides he has had enough of Woohyun's crying moping, he begins piecing together a puzzle he was forbid to a long time ago.