In Japan, hikikomori are individuals who isolate themselves from society, like Sasami Tsukuyomi who struggles to navigate high school as a shut-in. Luckily, her teacher brother Kamiomi lives with her and provides support. With her 'Brother Surveillance Tool,' Sasami observes the eccentric Yagami sisters and their peculiar fixation on Kamiomi. As she delves deeper, strange occurrences unfold—magical abilities, chocolate transformations, and a blurred line between online life and reality. Is Sasami's mind distorting from her digital world or is the universe spiraling into chaos?