After a sunlit summer, Futaro Uesugi teams up with the Nakano quintuplets, Ichika Nakano, Nino Nakano, Miku Nakano, Yotsuba Nakano, and Itsuki Nakano, as they enter their final year of high school and gear up for the school festival. The mood is affectionate but tense, because Futaro’s heart leads him to a confession: he loves them all in his own way, and he asks to wait until the festival ends to learn which sister he will choose. The moment is charged with hope, doubt, and the quiet tremor of impending change, setting the stage for a festival filled with moments that blur the line between friendship, duty, and romance.
On the festival’s second day, a dramatic turn unfolds. While taking part in the sisters’ acting work, one of them collapses, propelling Ichika into a hurried rush to the hospital. There, she encounters Futaro and Nino visiting, and the sight of them together deepens the emotional currents swirling around the group. Later, a quiet walk with Futaro leads to a tender kiss in a park, a small, intimate moment that hints at the complexity of Futaro’s later confession and the heavy choice before him.
Meanwhile, Nino faces her own test of family and loyalty. She awaits their father Maruo’s visit to the school, but cannot locate him among the crowd. When Futaro shares a video confirming his father’s attendance, Nino and Futaro head to the hospital to meet him. There, she cooks her father a simple pancake as a gesture of care, and after their reunion, she pulls Futaro into a kiss, thanking her father for selecting him as the quintuplets’ tutor. It’s a moment that underscores the ties between parental approval, affection, and the tutor’s impact on each sister’s life.
The festival’s first day shines with Miku’s energy. She accompanies Futaro toward the boys’ takoyaki stand and promises that the pancake-stand supporters will enjoy their treats. Yet calamity interrupts: the stand catches fire. The tension of the day dissolves into a rooftop moment on the third day, when Miku invites Futaro up and discovers two classmates arguing about the takoyaki incident. After reprimanding them, Miku’s jealousy emerges when she confronts Futaro and shares a kiss, revealing the emotional stakes behind the public stage of the festival.
Yotsuba’s unrelenting dedication to helping various clubs weighs heavily on her. She pushes herself to exhaustion, collapsing on the festival’s second day. In the hospital, she learns that some students who had benefited from her efforts offered to help in her absence—a reminder of how mutual support binds them all. On the festival’s third day, a resting Futaro is kissed by Yotsuba, sealing another thread in the tapestry of his relationships with the sisters.
Itsuki’s path intersects with a difficult truth. On the first day, she studies with focus while a teacher, Mudō, reveals a history with her mother. The next day brings a troubling discovery: Mudō is the quintuplets’ biological father, a revelation that sparks anger at his past abandonment. Yet on the festival’s third day, Futaro visits Itsuki at home, encouraging her to chase her dream of becoming a teacher. In a tense confrontation later, Mudō is confronted when Maruo, Isanari (Futaro’s father), and Miku (in disguise as Itsuki) meet to confront the truth; Itsuki bluntly tells Mudō that he is not suitable to be the quintuplets’ father, especially after failing to see through the disguise.
As the festival reaches its close, the sisters give Futaro a final invitation—to approach one of them in a moment when they are separated within a building and reveal his heart. The confession unfolds with Yotsuba Nakano: he confesses his love, but she initially rejects him, believing herself unworthy and unsure of the future. Yet the memory of their first meeting and a shared promise begin to guide her back toward him. In a heartfelt turn, Futaro catches up to her, and she opens up about her true feelings. The couple’s bond strengthens as Yotsuba decides to consider her sisters first before dating Futaro herself, setting the stage for a reconciliation that changes the dynamic of their relationships.
With forgiveness and connection prior to her own, Yotsuba moves forward, and Futaro’s persistence eventually leads to dating. The story then leaps five years into the future: Nino and Miku run a cafe together, Ichika has become an actress, Itsuki has become a teacher, and Yotsuba is preparing for marriage. As a wedding gift, Yotsuba’s ears are pierced to wear her mother’s earrings, a symbol of the family’s lineage and shared history. On the wedding day, the quintuplets stage a final game for Futaro, asking him to guess which sister will be the bride. Rather than choosing one, he identifies them all, a playful moment that affirms their unique bond. The wedding is a success, and the sisters discuss the best country for the newlyweds’ honeymoon, closing the chapter with warmth, humor, and a sense of lasting unity among them all.
