Becoming an idol is hard. Debuting is hard. Every year around 100 groups debute, only few of them survive. Kim Sojung, Jung Yerin, Choi Yuna and Hwang Eunbi have been trainees for years, waiting for their big day to come. Together with newbie Kim Yewon they are close to achieve this goal until a few months before their set debut date a member shockingly leaves the group and everyone in it in jeopardy. Will they find a new member? How well will she fit in? Will they succeed? A story about the hardships of debuting and becoming idols in an industry that has high - perhaps too high - expectations of young people who are still figuring themselves out.