"This might sound cocky, but I want to be my own person so I can stand shoulder to shoulder with you." VAZZY's brothers Issa and Futaba Kiduku receive an invitation to co-star in an original drama series. At first, older brother Issa is asked to play the straight-laced big brother Ryo and younger Futaba is asked to play the reckless little brother Itsuki. However, on the advice of show planner Taiga Orihara—an old rival of Issa's from his rock band years—the roles are reversed. While Issa's genius-level acting skills allow him to slip into his role with ease, Futaba struggles to take on the persona of an 'older brother.' Fellow Tsukino Productions members Haru Yayoi, Shiki Takamura, and Gaku Oguro then show up to form a new group called The Oniichans and teach Futaba what it's like to be a big brother.