Kouta, a highly effective but morally flexible home tutor, is assigned to teach the Kawai twins, two sisters who specialize in driving away their tutors through manipulation. After the twins attempt to blackmail him with a honey trap, Kouta decides to "educate" them and their mother using his own aggressive and sexual methods, asserting total dominance over the household.
Kouta, a tutor with a reputation for predatory behavior, is assigned to teach twins Kasumi and Mitsuki. While engaging in a secret affair with their mother, Chihiro, Kouta implements a "penalty" system for academic mistakes to coerce the daughters into sexual acts, using blackmail to ensure Kasumi's silence. He continues to manipulate the entire household under the guise of improving the girls' grades.