Ogawa to Yukai na Saitou-tachi

Rio Ogawa, fourteen-years-old, dreams of having good friends and a wonderful life, full happiness. But in reality, she is a slave to everyone at her school, especially to a girl named Mutsumi Narita. She orders Rio to get her food for her and tortures her to no end. One day, Rio is pushed into the cleaning cupboard at school, and is ordered to hit "The three feared Saitous" behind their knees. "The three feared Saitous" is three boys, each in different grades, who were ranked joint first in the questionnaire "The most feared" within the pupils. What happens when Rio refuses and bumps into them?