In Japan, there exists a term called hikikomori to describe individuals who have retreated so deeply into isolation that they resist leaving their homes for prolonged periods of time. Sasami Tsukuyomi can relate to this label all too well as she strives to pass her first year of high school while living as a recluse. Fortunately, Sasami resides with Kamiomi, her older brother, who happens to teach at her school. With her "Brother Surveillance Tool," Sasami can observe the outside world via her computer and attempt to reacclimate herself with interaction. However, her attention is often drawn to Kamiomi's interactions with the odd Yagami sisters who seem to have undergone a curious age reversal and an ethereal fascination with him. As Sasami bears witness to increasingly strange occurrences of magic and a transformation into chocolate, she questions whether her online involvement is altering her perception or if the universe is indeed agitated.