Nagisa is a third-year middle school student whose life revolves around supporting the super popular idol Wataya Reina. When she unexpectedly gets a short haircut during spring break, she is mistaken for a member of the boy idol group Dai-Ly... What's more, even though she's a girl, she ends up acting as a substitute for a missing member...?! The one who supports becomes the one who is supported! An eventful youth story of a substitute idol!!