One night while fapping to an erotic live stream, virgin NEET Yuuichi hears a mysterious voice, but he was unable to find where the source is coming from. The voice tells him that he has gained the power to make the unseeable seeable by getting a hard-on. Later that night, he leaves the house to buy some food, but he hears another mysterious voice again. He decides to use his newfound powers. Suddenly, a girl appears before him, and at the same time, his Twitter is blowing up. It turns out that the girl is a computer virus and has hacked his Twitter, saying embarrassing things in order to give him birthday wishes. After scolding the girl, Yuuichi tells her to "take responsibility," but she interprets this as her having sex with him, which Yuuichi gladly consents to. Afterwards, Yuuichi learns that the live stream he was fapping to that night was actually of his older sister masturbating. Yuuichi and his older sister were not the only ones affected by this. The same happened to many other guys that same night with either their older or younger sister, and it was caused by another virus. The guys, of course, did not realize until after the fact. Yuuichi and the girl who he just met decide to investigate his older sister's room to see if he can find any clues, but he soon hears another mysterious voice,... but this time, it's threatening him. Will Yuuichi be able to take out his penis and start rubbing it to get a hard-on to protect his older sister from other perverts or will he fail and the video could be spread to everybody?