This is the erotic debut of Ushiku Riona, the reliable office worker from the general affairs department who always puts others first. Even when she's not needed for anything, she's approached by many employees for her comforting presence. When she takes off her clothes, what's revealed is a pair of 'bouncy and soft, self-proclaimed F-cup breasts'. Witness Riona's first time experiencing SOD's signature multi-erotic tasks, despite her initial confusion and hesitation.