The swimming club performs better than ever at the prefectural meet and many members manage to qualify for the eastern regional tournament. Momoko has a little accident with her swimsuit, though, which even makes the school’s newspaper. Kaname, Amuro and Makio learn of the swimming club’s past. Kaname gets invited to a barbeque by Mirei, while Makio makes a website. Kaname and Amuro give swimming lessons at an elementary school and the Bust Building Alliance shows up again. Almost every club member has fun at the annual Onoshima Festival, although in the end luck runs out for some.
At the prefectural meet’s finals Maaya easily wins her race, setting a new tournament record and, as Momoko reminds Karena, giving Umishou their second consecutive win over Shinomiya. After Maaya’s race, on their way back from the toilets Amuro and Makio run into Taku Ikariya, Ikamasa’s younger brother, and thinking he is Ikamasa they comment on his changed appearance. When Ikamasa shows up, Taku reacts hostile towards him, saying it is insulting to have to swim with someone (Ikamasa) who does not take swimming seriously. Later, when Amuro and Makio have returned to the others, Momoko tells them she and both Ikariyas went to the same swimming school back in elementary and middle school and that their relationship has been as it is as long as she knows them. When Taku walks past, Momoko greets him and wishes the blushing Taku, who clearly has feelings for her, good luck. When the men’s preliminary 200 m butterfly race is about to start, it turns out Ikamasa and Taku are the only contestants. Wanting to beat his older brother, Taku focuses on beating Ikamasa right at the start, when the face Ikamasa has stitched to the front of his Speedos comes off. Catching the movement, Taku thinks Ikamasa starts and starts himself, getting disqualified for having a false start. As the race finally starts, Ikamasa manages to set a good time, making it to the finals.
Next up is the 200 m freestyle race, one of Momoko’s events. Even though she breaks her personal record, she comes in second place, after Karena, who claims Momoko only got a new personal record because of her. Momoko reacts that she will beat Karena in the 100 m race. At the end of the day Momoko is annoyed they only won three times (after Mirei and Maaya’s victories Amuro won the 50 m freestyle race) from Shinomiya, against six losses. Sanae counters that they performed much better than the previous year and managed to get people in all five events through to the eastern regional tournament. One of those is Ikamasa, whose opponents in the finals ‘for some reason’ had false starts, like Taku in the preliminaries. The next day starts with Taku winning the 100 m butterfly race and Sanae getting third place (still ahead of Shinomiya) in the 100 m breaststroke race. When Momoko repeats she will beat Karena in the 100 m freestyle race, Karena, confident she will win, suggests they make a wager: the one of them that loses will flash their breasts in front of the entire crowd. Not liking being called a coward, Momoko accepts the challenge. Their race starts and Karena immediately takes the lead, but then Amuro, who is in this race as well, quickly closes the gap, closely followed by Momoko. As the three of them fight for the victory, Kaname and Makio wonder who will win.
As Momoko, Karena and Amuro fight for the lead in the 100 m freestyle race, Kaname, Makio and Sanae move from the balcony to the pool side. After the 50 m turn Amuro is just in the lead, followed by Momoko and Karena. Not wanting to lose to either of them, Momoko speeds up as they approach the finish. Momoko wins and Amuro and Karena tie for second place. Momoko exits the water and reminds Karena of their wager. When Karena plans to flash in the pool, Momoko reminds her that the wager was to do it in front of everyone and tells her to get out of the water. As she stands next to the pool waiting for Karena to flash, her swimsuit tears right in the crotch area. As an embarrassed Momoko tries to cover her nether region, Amuro asks her if that is a standard ritual for the winner of this race. Kaname realizes the causes of this wardrobe malfunction must be the boys wearing the swimsuits the evening before the tournament and the thorough cleaning after Momoko discovered what they had done. Meanwhile Karena, not liking Momoko getting all the attention, decides to flash after all and as Manabu films this spectacle, Amuro comments to Kaname that prefectural tournaments are fun and that she hopes that next year Kaname will participate as well, before she starts flashing as well. Afterward, the swimming club celebrates its victories over Shinomiya and having seven people qualifying for the eastern regional tournament.
Three days after the prefectural tournament it is business as usual for the swimming club. While everyone is slacking off, of course angering Momoko, two members of the school newspaper arrive and announce they are doing a feature on the prefectural meet. Momoko, seeing this as a nice opportunity to improve the club’s image and generate some funds, warns everyone not to mess this up. Of course things do not go as Momoko hoped. After Mirei tells the reporters she won the 200 m individual medley, Amuro starts fondling her breasts, claiming those were the biggest in the tournament as well. Watching this, Maaya decides to hog the spotlight and claims she will dominate the interhigh tournament, but hearing the reporters are from the school newspaper she abruptly ignores them, angering Momoko. After taking a group picture, one of the reporters asks if anyone has photos from the meet itself. When several girls remember Takeda taking a lot of pictures, Momoko orders him to get his camera. Seeing a few photos with Umishou girls in them, she hands the camera to the reporters telling them to use any picture they like and delete any photos not featuring Umishou members. Takeda tries to protest and warn for something, but Momoko stops him by scolding and kicking him. Later, when the article is published it turns out Takeda tried to tell the camera had a picture of Momoko’s wardrobe malfunction as well and of course this picture is used for the article, resulting in the swimming club’s travelling expenses getting reduced even more.
After training, Amuro asks Sanae where Momoko is. Sanae replies she is at a meeting of all the school’s club captains to fight over the budget. When she tells that the lack of a proper advisor makes it harder, Kaname, Amuro and Makio want to know what happened to the advisor Kaname heard the club once had. This prompts Sanae to tell them about the creation of the swimming club.
Two years ago, just after starting at , Sanae and Momoko decide to make a swimming club, since the school does not have one. Momoko is about to give up on it, when they find the school’s pool in a terrible state, but Sanae convinces her to clean it up together anyway. Hearing this, a new teacher called decides to help them cleaning up the pool and forming a swimming club. When Ikamasa’s plan to form a mah-jong club failed, they talked him into joining the new swimming club as well.
Now knowing the origins of the swimming club, Kaname, Amuro and Makio still want to know about the fate of the teacher. Sanae promises to tell them, but warns them it is not a happy story.
After warning Kaname, Amuro and Makio again that it is a sad story, Sanae starts to tell them about how the swimming club lost its advisor.
With the pool ready for proper use, the new swimming club starts training every day and Tokorozawa-sensei has become like a friend of Momoko, Sanae and Ikamasa. One day, on their way home, Momoko tells Sanae she is lucky to spend so much time with improving her swimming. Sanae realizes Momoko has fallen in love with and promises Momoko she will help her by telling him how Momoko feels and when she does, tells her that he has fallen for Sanae. Sanae decides to comfort a heartbroken Momoko, who overheard the conversation and together they get drunk. When they start making out as well, they are interrupted by a policeman passing by. Both get house arrest and, since this happened during club activities, is forced to leave Umishou.
As Sanae concludes the story by telling that since then, the swimming club never had an advisor again and Momoko lost interest in boys, Momoko shows up. When Sanae suddenly remembers she has to go to a bookstore and leaves, Momoko asks the others what they were talking about. After some pressure, they decide to tell her and Momoko tells them that story is not what really happened. Sanae was the one that wanted to give up and barely helped and Momoko never had any interest in . Sanae pretended to be, though and he took that seriously. Not liking that, she accused him of sexual harassment and had him fired. Seeing Kaname, Amuro and Makio are not convinced yet, Momoko shows them a group picture of the original swimming club with in it as well. Seeing he does not look the way Sanae described him, they start to doubt Sanae’s story. When they pass a bookstore, they spot Sanae using her charms to get an extra discount, which for them is enough proof that Momoko is telling the truth.
Mirei has invited Kaname to a barbeque at her family’s villa in the mountains. After dinner, her parents go for a walk, leaving the two of them alone. Mirei explains to Kaname that whenever they visit the villa, her parents will go for a walk after dinner, leaving her alone. Mirei admits being afraid when left alone at the villa, since during an earlier visit she spotted a bear nearby. She explains that she asked Kaname to join her because of that and shows him a can of bear repellent she brought just in case. When she tells him she is especially worried about something happening to her parents during their walk, Kaname thinks she is very pure and he never should have judged her by her underwear. He decides to confess taking her panties after finding them and apologize for this, but Mirei has fallen asleep. Suddenly he spots what looks like a bear in front of the windows and panicking he wakes up Mirei and reaches out for the bear repellent spray. Instead of the spray he accidentally grabs one of Mirei’s kokeshi. Meanwhile, Mirei notices the bear is actually her father. He and her mother, dressed in a bear suit as well are just outside the villa in the middle of one of their cosplay games.
Makio wants to make a website for the swimming club. When she mentions they can ask for donations on its front page, Momoko reluctantly gives her permission. When the others are not impressed by her first attempt, she reads about web pages and starts all over again. This time it looks much better… until they arrive at the member introductions. It turns out Makio decided to use all kinds of whacky manipulated pictures for each member. After the knowledge of the page spread quickly through the school, the club’s funding was cut back even further. They quickly shut down the site, but the pictures had already spread across the internet.
It is July, the start of the pool season, and every year the swimming club sends two members to the local grade school to help teaching the children how to swim. Momoko, who went the previous year with Ikamasa, wants two second years as volunteers this year. Takeda volunteers, but of course is thought of as too dangerous. When Amuro volunteers, Momoko decides Kaname should be the second ‘volunteer’, since according to her he is the only reliable guy in the club. Despite a bit of a rough start (the kids all asking sex related questions), Amuro proves to be really good with children and does not get embarrassed when they ‘accidentally’ touch her. When the kids see her swimming skills, they all want to be taught by her, despite her hitting her head at the far end of the pool (again). When teaching the kids how to swim like her, she of course forgets to watch out for the far end of the pool again, resulting in her and all the kids crashing into it, damaging the pool. As a result, until their pool is repaired the kids get swimming lessons at Umishou’s pool, making training for the swimming club almost impossible.
Maaya is having lunch by herself on the school’s rooftop, when Makio shows up and after asking Maaya if she has any progress regarding her breast growth, she suggests asking someone with big breasts for advice. Suggesting asking Amuro leads to a strong reaction from Maaya, so in the end Makio talks Mirei into being their advisor. She takes Mirei and Maaya into a stall in the girls’ restroom, so they have some privacy and asks Mirei when and how her breasts got that big, while Maaya acts hostile towards her. Having to say something Mirei tells them a story of visiting a farm and seeing a cow’s udders when getting milked, wondering if her breasts would become like that and then they started to grow. Maaya is sceptical, but Makio believes that Mirei’s story contains the solution: she and Maaya have to think they will get bigger. Claiming they need some image training, Makio then talks Mirei into showing them her bare breasts. Mirei reluctantly shows them and Makio cannot resist touching them. She tells Maaya to join her, shocking both Mirei and Maaya. Maaya angrily leaves and refuses to talk to Makio. After some time Makio bumps into Maaya, trying to apologize. Maaya drops her bag, spilling its contents: magazines featuring large breasts and photos of cows. For Makio this is proof the Bust Building Alliance has reformed.
Kaname visits the annual Onoshima festival together with his mother, Amuro and Masashi. Shortly after arriving, Amuro drags Kaname with her so they can visit the different stalls together. After some time they run into Makio, Momoko, Sanae, Mirei, Maaya and Iori. Ikamasa turns out to be at the festival as well: his family runs a fish scooping stall and when he sees his fellow club members, he begs them to help him by having a scoop each, while his dad wonders if they are willing to do so in swimsuits again. Instead of the usual goldfish, the Ikariyas are using all kinds of expensive fish, including fugu. Makio gives it a try, but due to the weight of the fish, the scoop breaks, as planned by the Ikariyas, who are of course not willing to lose all their money. But what they held for impossible happens: when Amuro gives it a try, she keeps on catching fish. Seeing this, the Ikariyas decide it is time to ‘level up’ and fill the water tank with eels. Of course an accident is bound to happen, as some eels get caught inside of Momoko’s and Mirei’s yukata. Momoko’s screams for help are heard by Taku, who is strolling down the market. Recognizing Momoko, he quickly rushes to help, but accidentally pushes her too hard against the water tank, breaking it. After Momoko punishes the two older Ikariyas and tells Taku he does not have to apologize, they hear a message over the PA system. It announces that the Luck Run is about to start. In this two mile race, held once every four years, the winning couple is supposed to have good luck until the next race. As the others contemplate joining, Sanae spices things up by stating the winners will be 100% romantically linked, leading to Taku enthusiastically accepting Momoko’s invitation to race together and several girls fighting over Kaname.
At the start of the Luck Run, its committee’s president, Ikamasa’s father announces they set up several obstacles to make the race more fun. Right after the start it becomes clear what he meant, when the leading group is caught in a net falling from the skies. Amuro is nearly eliminated by the next trap, a directional arrow pointing to the edge of a cliff, but she manages to use her sash as Indiana Jones uses his whip and saves herself. Makio is less lucky and ends up in the water. After some time only nine people are left, including Ikamasa, who was told by his father where all the traps are. But being an idiot, he manages to still activate a trap and he and several others, including Maaya and Amuro, get caught in another net, resulting in five people, Taku, Momoko, Kaname, Mirei and a mysterious woman, still being in the race. Taku, grabbing Momoko accelerates, thinking they will win, but they are overtaken by the woman, who has grabbed Kaname’s hand. Just when Kaname realizes the woman is Iori in disguise, Mirei’s sash gets undone and her yukata falls open. Both Momoko and Kaname manage to free themselves from their ‘partners’’ grips and rush to Mirei to help her, resulting in Taku and Iori winning as the lucky couple.
While Kaname’s group is struggling at the Ikariyas’ stall, Takeda, Jun and Isao are trying to pick up girls at the festival. After Isao and Jun failed, Takeda tells them he will show them how it is done and approaches an elementary school girl. When the girl’s mother arrives the three misfits quickly run away. After escaping they spot some new targets, older this time and try again. This group of four turns out to be Karena and three other Shinomiya swimming club members. Karena of course quickly turns down Takeda and leaves, complaining about the ‘boring festival’. The other three stay behind and one of them, Tomoko Naruko, asks the three Umishou boys if they would like to join them lighting some fireworks, since Karena has left them behind. Despite at first not liking how the girls look, they decide to join them. The six of them have fun lighting fireworks and talking to each other, but just when Takeda is about to kiss Tomoko, together with the little girl and her mother a police officer arrives to question the three boys.
This chapter consists of a series of short bonus stories, each focusing on one or two characters.
Kaname is awoken by the barking of Lala, only to find Amuro is feeding the dog next to his bed. He discovers the Ninagawas have put up a tent in the room they are staying in and that they like something called “A1” for breakfast, which Amuro decides to go buying, dragging Kaname with her.
Makio and Maaya both are dreaming that one day at training they both have big breasts, while all the other female members’ breasts have become tiny. The dream becomes really weird when the boys show up, all having large breasts as well.
On her day off Momoko is on her bed reading a manga and having a snack, when Sanae messages her asking if she wants to go to karaoke. Wanting to just stay at home, Momoko declines and also refuses to go buy cigarettes for one of her parents.
On their search for “A1”, which the convenience store did not have, Amuro and Kaname run into Sanae, who just received Momoko’s message. When Amuro asks her where they can get some “A1”, Sanae, not knowing what it is either, tricks them into joining her for karaoke.
In their restaurant, as they claim the liveliest place in , the Ikariyas are sleeping when miraculously a customer enters. The customer remarks there is a wet spot on the bar, to which Ikamasa replies it is their drool, causing the customer to leave, allowing the Ikariyas to go back to sleep.
Takeda visits an arcade and puts in high score after high score on each of the games. Hours later, he is out of money and hungry.
Ono-chan’s typical day consists of lazing about while avoiding getting caught by Masashi.
Maaya is posing in front of the mirror to see how cute she is. She gets annoyed though when she realizes one of her poses mimics Amuro.
Iori, stating he has a fingertip fetish, visits a bookstore and spots some fingertips he likes holding a book. He imagines they belong to a good looking boy, but in reality they are Manabu’s.
Visiting a store, Mirei spots a penis sheath. She really wants it, but is too embarrassed to buy it. In the end, when the shop owner asks her what she wants she, eyes closed, points in the direction of the penis sheath, but when she opens her eyes again, she realizes she just bought an elephant statue.
At the Ikariyas’ restaurant Ikamasa’s father is asked by some regular customers if he has a new girlfriend since his wife ran away years ago. Trying to remember the name of his most likely fictional girlfriend, he mutters “Momoko”. When Momoko enters the restaurant to get back a DVD Ikamasa rented and he greats her, she gets funny looks from the customers.
After having gone to karaoke with Sanae and by now having given up finding any “A1”, Amuro and Kaname are walking down the beach. Amuro asks if he remembers the place, to which he replies it is the place they first met. She tells him again that it was the second time; the first was at Chura Umi. As they move on, they spot a bottle of sauce, which turns out to be the mysterious “A1” and other stuff from Amuro’s house that was lost in the storm.