Miko Iino is a member of the discipline committee with a strong sense of justice and a refusal to tolerate injustice. She secretly has a crush on a certain online singer. Excited by an invitation from her idol, she goes to meet him, only to find that the man she admires is an obese man who looks nothing like what she imagined. However, the moment the man opens his mouth, his sweet, irresistible voice touches Miko's brain.
"This is just a part-time job to learn about society," she says.
With those words, her firm resolve crumbles. For the sake of her teacher, for the sake of the school... she tells herself, as she gives herself over to the man. What began as a simple act of obligation grows more intense with each passing moment, eventually imprinting a sinful pleasure on her body. Before she knows it, the faces of her fellow student council members and the words of justice she once believed in all pale in comparison to his sultry voice and the pleasure he brings.