They dated in high school and being apart when they graduate.
GF went to city while MC still back home.
GF feel lonely and senpai at welcome party are try to approach her. She didn't aware and let him inside her house, get raped.
GF reach to MC but he busy gaming with his friend and half -heart replied to her. GF left with more lonely and said 'fuck that' and submit to his Master.
And the rest it's just your typical NTR she went back home and show the video to MC and lastly she said that she love him very much at her first love.