Half a month into their summer vacation, Kaguya spends her days moping around, unable to see Shirogane without the student council to throw them together. However, she does have plans to see a fireworks display with the other members of the student council toward the end of the break. Kaguya has never been able to make summer memories because of her strict upbringing as the daughter of the head of a financial conglomerate, so she is anticipating the day she can have fun with everyone. But the day before the event, Kaguya's father suddenly summons her home to Kyoto...

Shirogane is at the top of the race for the student council elections according to the latest predictions, but he is concerned about Miko Iino, a first-year who is trailing close behind him in the race. His competitive streak flares up when he has a conversation with Miko during her election campaign and finds out that she has been at the top of her class as well as an eloquent speaker. Fujiwara plays the role of the peacemaker while tensions mount between the two rivals, but she is caught off guard when Miko asks, “Will you be my vice president if I’m elected as the student council president?”

Ishigami has a biased opinion that "Guys who wear boxers are all man whores." Kaguya takes his words to heart and is dying to know what kind of underwear Shirogane is wearing. She tries to come up with different strategies so that she can take a peek at his underwear without it seeming weird, but all her ideas are too naughty. She decides to ask him directly what kind of underwear he likes, but Shirogane misunderstands the question and thinks she is asking him what kind of lingerie he is into. Shirogane starts to imagine the kind of underwear that he wants Kaguya to wear.

Shirogane accidentally steps on Maki Shijo, a female student who had collapsed on campus, and takes care of her in the student council room. Apparently, she has suffered from the sorrows of love. When Maki discusses her situation with him, her expression changes from high-spirited, to anxious, to explosively angry, to tearful. After witnessing such an intense range of human emotion, for some reason Shirogane was struck by a strong sense of déjà vu. What on earth was this feeling?