The gloomy otaku Sumire got a stepbrother due to her mother's remarriage and started living with him. Sumire, who has just gotten a little brother, loves him dearly. Sumire, an otaku shut-in who can't suppress her feelings for her stepbrother, whispers obscenities in her unique creepy way of speaking while obsessively loving him. Her uncontrollable love escalates more and more!
