The teacher asks Akiyama, a geeky boy, and Ieda, a popular jock, to visit Noriko's house because she's been absent from school for some time. Akiyama and Ieda find Noriko, a pretty girl, alone at home. They assume Noriko hasn't come to school because she has not been feeling well, but to their surprise, it turns out that she has another type of illness... she can't stop thinking about sex. Before Akiyama and Ieda realize what's happening, Noriko insists that they have a threesome. This intimate act bonds them as friends forever.