W furin: Netorare tsuma to shô akuma musume.

Yoshinaga, a doctor of psychology, is immersed in writing a book, and as he conducts research using his wife, Emiko, as a test subject, he discovers that Emiko has the potential to be a sadist. the next day. After reporting last night's induced pleasure act to Yoshinaga's good partner, associate professor Muraki, he later assigned Muraki's ex-girlfriend, Hitomi, as Yoshinaga's full-time secretary in order to repair their marital relationship. Meanwhile, Shoko, a fourth-year university student, comes to visit Yoshinaga to ask him to do something about her not being able to meet the deadline for her report...