Si-yoon, the leader of the idol group in their eighth year ⟨Nu-Bois⟩ died in a truck accident on his way to a press conference because of a drug scandal involving a group member.After that incident, he regressed back to his days as a trainee ten year ago, adopting a new mindset to establish his position to become an idol.Along the way, he pushed out the group members prior to regression to form a group with the members that he wanted, but…Will Si-yoon, the all-rounder idol, who did everything from the production to the promotion, be able to make a successful debut?"