Uchi no Seiso-kei Iinchou ga Katsute Chuunibyou Idol Datta Koto wo Ore Dake ga Shitteiru.

Once known to the world as "Mare," the wildly eccentric idol Nightmare Disaster captivated audiences everywhere with her over-the-top chuunibyou persona. Behind the scenes, Leo worked tirelessly to fuel her meteoric rise, snapping photographs and orchestrating viral social media campaigns to keep her in the spotlight. Now a high school student, he unexpectedly crosses paths with his former client, only to discover that the flamboyant star has completely vanished. In her place stands Nagi Juunana, a quiet, socially awkward introvert who serves as their class president and seems determined to leave her theatrical past behind forever. Despite her reserved nature, Nagi harbors a surprising ambition: she wants to run for student council president. Realizing she cannot navigate the campaign alone, she turns to the one person who understands the mechanics of public appeal, asking Leo for his help. Thrust back into the role of manager, Leo finds himself strategizing for an entirely different kind of stage. With no one else aware of the secret connection between the shy class representative and the legendary idol she used to be, Leo must use his old promotional skills to guide Nagi toward victory while protecting the hidden truth they share.