Sasami discovers a DVD containing a project by Kamiomi and the Yagami sisters involving them filming her in secret to record her progress. Putting the somewhat perverted nature of the DVD aside, Sasami can't recall doing any of the actions displayed in the video. As Sasami in the video winds up at a mini live concert, it turns out to be a trap set up by the Tsukuyomi Shrine, in which Sasami's father stabs her third arm and allegedly steals her power of Amaterasu. The video soon reaches its climax involving an all out battle between the shrine, the Yagami sisters and government forces trying to obtain an alien Tama came across. Tsurugi then explains that the DVD was made to explain things to Sasami, who is actually revealed to be the third arm, a sarcoma, who lost her memories and assumed she was Sasami and took her form. Sarcoma objects to being forced to return to Sasami's body, but Tsurugi takes away her power before she can object.
The Japanese call them hikikomori-people who've become so withdrawn socially that they refuse to leave their homes for weeks and even months at a time. For Sasami Tsukuyomi, who's attempting to pass her first year of high school despite being a shut in, it's more than just a word. Fortunately though, she lives with her older brother Kamiomi, who just happens to be a teacher at the school Sasami is supposed to attend. Not to mention, her "Brother Surveillance Tool" which lets her view the outside world via her computer and will, theoretically, allow her to readjust to interfacing with people again. What it mainly does, however, is let her view her brother's interactions with the three very odd Yagami sisters, who inexplicably seem to have had their ages reversed and have various types of "interest" in Kamiomi. And then things start to get really weird... Magical powers? Everything turning into chocolate? Is life via the web warping Sasami's brain, or is it the universe that's going ...
