Sumire, a gloomy introverted otaku, starts living with her new stepbrother after her mother's remarriage. She absolutely dotes on her first-ever stepbrother and finds him irresistibly cute. Unable to contain her feelings, Sumire's otaku nature takes over as she obsessively showers him with affection, whispering lewd words in her uniquely creepy way of speaking. Her uncontrollable love for her stepbrother runs wild and continues to escalate!
