As term-end exams approach, the psychological war between Kaguya and Shirogane in the student council room ramps up. Kaguya is an all-around genius, but her pride is hurt because she hasn't yet beaten Shirogane when it comes to academics. Meanwhile, when it comes to making an effort, Shirogane is second to no one and as the president of student council, he refuses to let anyone else usurp his position at the head of the class. The two of them lie through their teeth and employ wiles worthy of Machiavelli in an attempt to get ahead of the other. At last, it's the day of finals, but which of them will the goddess of victory smile upon?

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...

Kaguya finally gets to go window shopping and watches vigilantly for her chance to befriend Shirogane’s sister, Kei. While the Fujiwara sisters get in the way, she eventually manages to position herself next to Kei. But then, she can only see Shirogane’s resemblance in Kei’s profile, making her heart beat wildly out of control. Kaguya still decides to take the opportunity to figure out what she should give Shirogane for his birthday when Kei mutters that she isn’t very close to her brother. What secrets will Kei spill about Shirogane?

The student council is asked to model for the Shuchiin Academy brochure. However, Kaguya's family has a strict policy prohibiting her from being photographed for any forms of publicity, and as result, she is unable to participate. As Kaguya longingly observes the rooftop photo shoot, the student council members propose to take a final group photo, solely for private use, on their cell phone, which makes Kaguya very happy. Just then a gust of wind blows across the rooftop, causing her to drop her phone and sending it way down below to the school grounds. Kaguya picks up her shattered cell phone from the floor and begins to reflect on all the photos with everyone she has lost, and becomes overwhelmed with sadness.

Kaguya learns about the romantic legend that giving a heart-shaped gift at the Culture Festival brings eternal love. She wonders if there is a way she can give Shirogane a heart-shaped gift without getting caught. But her plans are full of errors, and she panics. She becomes sick of herself as a cowardly person who can only come up with negative ideas. There, Shirogane, exhausted from preparing for the Culture Festival, shows up. As Kaguya sees Shirogane doing his best for everyone as the student council president, she...

Ishigami, who succeeded in inviting Tsubame on a Culture Festival date, browses around campus exhibits in an attempt to shorten the distance between the two. In the end, it didn't go as well as hoped. But when he tried to express his everyday feelings of gratitude for the upperclassman he feels indebted to, it caused an unexpected uproar. Shirogane was astonished after witnessing the unexpected event. Gripped by the fear that his secretly planned "Make Shinomiya Confess Plan" will be ruined, he sinks into despair after thinking too hard about every detail.