The most admired job by the teens in Korea is being a world-renowned idol. Annually, 30 to 40 groups make their first appearance, but success is not promised to all. Only a handful get the spotlight, and the rest are underestimated for various reasons. The Unit approaches them to redevelop the hidden potentials and to regroup them as a whole new unit. Rain, Hwang Chi Yeul, Hyun A, Tae Min, San E, and Jo Hyun Ah are the mentors who will evaluate the Ex-idols who seek for their dreams again.
The members get challenged by missions such as music video shoot, reinterpreting the famous idol songs, position battle, and even self-producing the whole performance. Through the competition, the nine final members of Unit G and Unit B is selected. Who will become the final member of The Unit?