I wonder if I'm not attractive as a girl ..." Miku worries about Yuukiya's indifferent attitude, so she casually confides in his sister, Wakana, who recommends shojo manga. There, Miku discovers something that the two of them "haven't done yet." That is ... ...a sleepover! As Miku's imagination runs wild, she remembers how they used to do that as a matter of course.

One rainy morning, Miku visits Yuukiya's house
to wake him up. Miku is captivated by his defenseless sleeping face, while Yuukiya is flustered by her sudden visit. As they walk to school together under the same umbrella and engage in some playful banter in secluded places, their hearts begin to beat faster and faster. However, their moment is witnessed by the strict and charismatic student council president, Shirayuri Kazane ...!?