Fireworks Festival Arc is covered in Volume 2.
- Start of the arc: Fuutarou Uesugi and the Nakano Quintuplets are having a day off (Chapter 7)
- End of the arc: Ichika Nakano reconciles with her sisters and asks Fuutarou to get their contact address (Chapter 13)
After tutoring the Nakano Quintuplets for two days, Fuutarou Uesugi receives his first paycheck. After reluctantly accepting it, Fuutarou uses the money to entertain Raiha Uesugi (Fuutarou's little sister), who requests they use it to visit the arcade together. On their way home, they meet the other Nakano Quintuplets, who are about to visit the Autumn Fireworks Festival together. The seemingly happy occasion is disturbed when the sisters get scattered and Ichika Nakano goes missing.
This arc is about the firework festival, the Nakano Quintuplets' plan to watch the event together and the importance of the events for them.
Having A Day Off (Chapter 7)
While planning his next tutoring session with the Nakano Quintuplets, Fuutarou Uesugi was visited by Itsuki Nakano who gives him his first paycheck, to which he spends it to entertain his sister, bringing her to an arcade. Accompanying them there was Itsuki who was unable to reject Raiha Uesugi (Fuutarou's little sister). With that, the three played all sorts of games there and even took a picture together. As they were about to leave, the other four of the Nakano Quintuplets, wearing yukatas, appeared and invited Fuutarou and Raiha to join them for the festival. ("Our Day Off 1")
Before the start of the festival, the Nakano Quintuplets were forced to finish their homework by Fuutarou Uesugi. After doing so, the group then went and enjoyed the festival to their hearts content. Fuutarou learns from Miku Nakano that they would always go and watch the fireworks together even after their mother's death, because it made them remember their time together as a family. After dealing with a large crowd, the group got separated from each other causing Fuutarou and Nino Nakano to watch the firework spectacle atop with the others located somewhere in the festival. ("Our Day Off 2")
While the fireworks display was going on, Fuutarou spots Ichika Nakano only to be stopped by a middle aged man. He also manages to find Miku who had hurt her foot and he ends his search for the eldest quintuplet (Ichika). Separating from Miku, he finds Itsuki Nakano in the crowd before getting approached by Ichika who tells him to pass a message saying she is unable to watch the fireworks with her sisters. ("Our Day Off 3")
The Failed Plan and the Problematic Sister (Chapter 10 & 11)
As Fuutarou Uesugi stops Ichika Nakano from leaving without explaining herself, Ichika asks him why he cared about her personal business to which he tells himself that he shouldn't be involved with other people. Ichika's 'colleague' passes by the alleyway that they are in to see Fuutarou hugging Ichika. Ichika then reveals to Fuutarou that her she works as a photograph assistant. That was when the man shouted out that he had found her and the two watch him drag Miku Nakano, who had changed her hairstyle, away. The question revolving his relationship with the quintuplets gets brought up again and with full of confidence, Fuutarou claims that he is their Partner. This is right before Ichika's true job as an actress revealed. ("Our Day Off 4")
Fuutarou continues to ask Ichika regarding her job, telling her that he has a supporting relationship with each of them before she tells him about how she can make her movie debut if she passes the audition that's held on the same night as the fireworks display. Fuutarou and Ichika then practices her lines for a bit before Fuutarou tells her to put her fake smile away, claiming that she's also been hiding her true feelings. He then tells her about the debt his family owe and how he wants to help make his salary more meaningful by helping them out. Ichika then arrives at the audition hall and with her sisters' and Fuutarou coming to mind, she manages to flash a large, genuine smile on her face while Yotsuba claims that the "preparation" is done. ("Our Day Off 5")
Aftermath (Chapter 12 & 13)
Fuutarou brings Itsuki Nakano over to the park where the others were, playing with small fireworks that Yotsuba Nakano bought while in the festival. Nino Nakano then thanked Fuutarou for his help as she began scolding Ichika Nakano for not telling her sisters' about it before confessing that she had made a mistake as well by not telling everyone about where to meet up. The others followed in suit, partly blaming themselves for missing the fireworks display. They then reminded themselves of the Gotoubun Principles, something that had been told by their mother, that if one of them were to screw up, the five of them would then overcome it together. As the night passes on, Ichika places the sleeping Fuutarou on her lap as she thanked him for helping her. ("Our Day Off 6")
Fuutarou gets greeted by Ichika as he was walking to school where she tells him that she had told her sisters' about her job as an actress, to their shock. Ichika then hands over phone to exchange email addresses, which was supported by Yotsuba who had to leave the study group to help a teacher. Ichika then threatens Fuutarou to get everyone's email addresses with a picture of his sleeping face. After managing to get Miku Nakano's, he went to Nino and Itsuki who both refused, but managed to get them in the end. He was about to get Yotsuba's one as well but a sudden call from the Basketball Club causes her to leave once again, but this time she was followed by Fuutarou. As soon as she arrived, she was asked to join the Basketball Club but she refused, claiming that she has things to do after school. Fuutarou, surprised and happy by this, tells her that they have a lot of studying to do and that she better prepare herself. Later that night, Fuutarou gives the girls' homework through their email addresses, making them regret doing so in the first place. ("The Amiable Pushover")
- Fuutarou Uesugi receives his first pay and Itsuki Nakano says that he started a change among the sisters.
- Watching fireworks together is a tradition for the Nakano Quintuplets and Rena Nakano (the Nakano Quintuplets), in which the event is an important memories for them.
- Ichika Nakano is seen being together with a man and leaving the festival, opt to not joining her sisters.
- Ichika has a job as an actress.
- Fuutarou tells Ichika about his family's circumstances.
- Gotoubun Principles is first described: the Nakano Quintuplets are supposed to share every emotions (joy, sadness, anger, love) with each other and split it in five equal parts.
- Fuutarou obtains the Nakano Quintuplets' phone address.