Sakuta Azusagawa watches his girlfriend Mai Sakurajima wake up one morning inside the body of her younger half-sister Nodoka Toyohama, an idol in the group Sweet Bullet, while Nodoka wakes up in Mai's. Adolescence Syndrome has swapped them just as Nodoka's group heads into concert preparations, forcing both sisters to fake being each other while Sakuta tries to keep the switch secret. This manga adapts the fourth Bunny Girl Senpai light novel, the "Siscon Idol" arc.