The 'familiar' space becomes an 'unfamiliar' stage of mystery! The seeker! The hider! The one trying to hide! Korea's first undercover mystery variety show! 'Unknown' actors ready to 'step out'! Popular stars, 'famous' actors, step in as the 'designers' of the mystery stage for them! And the 'Celebrity Detective Squad' challenging their mystery stage! Popular stars who lead from acting direction to coaching for the unknown actors, and the 'Celebrity Detective Squad' who suspects and observes every glance, tone, and gesture! A breathtaking battle of nerves! Will the 'Celebrity Detective Squad' be able to find 'Kim Moo-myung,' who is hiding within a specific group and performing 'method acting'?