Based on the erotic game by Lune. 
 
Morishita Wataru grew up on a motherless family, but despite his lonely environment, he worked hard and managed to enroll in the prestigious Ousei Academy. The school is run by an old scholarship rule, in which the students' grades are tied to the teacher's evaluation, so the teachers inevitably gives the students a strict education. 
 
Morishita has good grades, but in a class where everyone is an excellent student, his grades were below-average. His homeroom teacher Tsukishima Kyouko was particularly strict on him, whenever if it's about his grades or even his daily life too. Morishita was very stressed between the difficult studies and the harsh teaching, but he had someone to help him: Shirakawa Miwa, a kind, maternal woman who is the assistant homeroom teacher of his class and understood Morishita's circumstances, all of this made Morishita developing romantic feelings towards her. 
 
However, she suddenly announced her marriage, and Morishita who lost his friend and only moral support fell into despair. Naturally, he couldn't concentrate anymore on his studies and end up getting the lowest score on the scholarship test, leading to take special classes after school. 
 
His stress was bigger than ever, now Miwa was going to become another man's wife and his grades lower than before. At this moment, his smartphone started to vibrate, and when Morishita checked it out of curiosity, there was an app he had never seen called "Hypnosis App" on the screen... 
 
(Source: Visual Novel Database)

Kyonyuu Hitozuma Onna Kyoushi Saimin