In order of appearance:
Kairi and Hikaru are at Seiyo Academy: Kairi is trying to take Hikaru to the garden, but Hikaru tugs on his shirt and tells him the garden wasn't in the direction he was going, but a different direction. Hikaru tells Kairi that he knew the map of the school by heart already, confusing Kairi a little, and Musashi comments that, like always, Kairi had no sense of direction. Kairi is telling Hikaru the next place they would be going on their tour, but doesn't finish his sentence, for he had noticed something. He wonders if what he and Hikaru are looking at was on the map too, "it" being a huge ball.
The two get surprised when it moves, opening up to reveal Yaya and Pepe. Kairi is freaked out and asks why the Ace was in there and says that there was a story of Momotarou being born from a peach, but lets his sentence trail as he doesn't know what to say about this. Pepe calls him a punk and says that since they saw this that she was going to have to kill them. She calls Dear Baby's Duckies to sic him, but Yaya, blushing and looking annoyed, tells him that even if he had seen it, she didn't care and calls Pepe and the Duckies off. She goes on and tells Hikaru and Kairi that since they weren't graduating it was okay for the time being. The boys find out that the big ball was for a celebration of the Guardians' graduation. Yaya says that after the celebration she wanted to take a picture to commemorate the moment and as the picture was being taken, she would pop the ball open. She adds she wanted to make it a yearly tradition and Kairi sees she wants it to be customary.
Yaya goes on and tells them that only the youngest Guardian, whatever the year, would be able to choose what would go in it at the time. At the moment, for her, she couldn't figure out what to put in it, so Kairi tells her that usually items that went in a ball were brightly colored pieces of paper and streamers, but Yaya cuts him off and throws a fit, saying she didn't want it to be normal and that it had to have "Yay!"and "Whee!" and "Hooray!" in it. Musashi thinks over the three aspects Yaya wanted and Pepe translates it for him, saying it had to be things that would surprise people.
Yaya smiles and comments on the fact that their Guardians were graduating and tells them that was why she wanted to try her best alone and says that even if they graduated, she knew that the Guardians were going to be okay. Hikaru tells her that without help that she wouldn't get certain things that called for physical activity accomplished. She grumbles and says that she knew that, but says that it would work out in the end because she was the Ace. Kairi calls to Yaya and asks if he could help since his sister's wedding was going along well, he had some free time and says that he was finished showing Hikaru around the school; Hikaru saying he didn't have a problem with helping either. Kairi smiles and tells her that she wasn't alone and asks if they should go around town looking for things that made people go "yay" and "whee" to which Yaya happily agrees.
The next day, Yaya's running toward Hikaru and Kairi apologizing for making them wait and wonders what Kairi was doing. He was counting down the seconds to ten o'clock and when ten a.m. and zero seconds come by, he tells her that he and Hikaru hadn't waited a single second, causing Yaya to be surprised he was going straight to the second. He says that to be on schedule they would have to go straight to the second, and adds that they had just wasted twenty of them. He brings up a scroll, shocking Yaya who asks if it had secret ninja techniques, but he tells her it was their schedule for the day. He begins to list off what they were to do and at what times, causing Yaya to grip her head with both of her hands and yell, asking what kind of schedule he had prepared for it was too crazy. He tries to tell her that it wasn't crazy and to do it properly they would have to go by it, but Yaya interrupts and says that they weren't doing work, but rather, looking for things that went "yay!" and "whee!"; fun things.
She asks Kairi to think about what would be fun to put in the ball and, as he thinks, Musashi and Pepe give their opinions: Pepe saying lots of candy while Musashi goes with provisions for the troops, but that gets a "no." Pepe suggests lots of balloons and Musashi says aerial tactics, which gets another "no." Hikaru, with a blush, asks about lots of pretty rocks, but Pepe says that that was more of a punishment. Kairi is still thinking when Yaya screams, so he asks if she had found something and she replies saying she had found a new crepe shop, saying that they should go get some. Kairi rejects the idea and says that he thought she had found something. He brings out the schedule and begins to tell them something, but Yaya rejects the schedule, saying they didn't need one to look for fun things; that they just had to have fun. As Kairi looks on, Yaya asks Hikaru what flavor crepe he wanted and he responds with "taiyaki flavored," but Yaya doesn't think they had that flavor.
After they buy some crepes, Hikaru says that it was just like taiyaki while Yaya notices that crepes had plenty of different flavors and asks Kairi if he was glad they had went to get some. Pepe sees that Yaya was happy and she wonders if she was and laughs, causing Kairi to smile and say "that's our Ace." Yaya suddenly tells him to stop and points a finger at him, scaring him. She tells him that he only called her Ace and that he should call her Yaya as it was a very cuter name than "Ace". He gets confused and she tells him she hadn't even called him "class prez" at all the whole day and he asks if that were true, but she gets defiant and says that if he didn't call her "Yaya" she wouldn't listen to him. He asks why she was willing to go that far to Hikaru's comment of "it was a mystery" and Pepe's of "that it was just Yaya".
Across from where the three are standing, Yaya sees a woman promoting and handing out flowers. Yaya gets a poppy and exclaims over the fact it was so cute, but Kairi notices that they were getting distracted again. He then gets an idea and calls to Yaya, calling her Ace though she does listen, saying they should put flowers in the ball. She gets excited as it was a good idea and says that there should be lots and lots of spring flowers, but the only problem is that they needed a lot and that they couldn't get them from the school's garden. Hikaru tugs on Kairi's jacket and holds out a flyer of which is promoting a big flower race where the prize was one thousand poppy flowers.
An announcer at the flower race is saying that the race was starting and Yaya yells out that they were going to win while Kairi notices that they ended up there somehow, though he does have a slight smile. The announcer shows to audience and participating crowd the prize and says that the first round was a trivia quiz. The first question is who is the "matabee" cherry blossom named after, and Yaya says it was too hard, but Kairi hits the bell and yells out "Gotou Matabee" to the announcers reply of a correct. Kairi tells them to leave the history questions to him and adjusts his glasses. The next question their team also gets and Yaya compliments Kairi on how fast he answered the questions; he saying it was a master swordsman's technique as he adjusts his glasses again.
He looks at her, calling her Ace again, and says that she was the spectacular one, to her confusion. He says that even though they moved from their original plan, they found a solution to their problem and tells her that she was Seiyo Academy's Ace. Blushing very hard with a smile, she turns away and shoves him on his arm playfully and calls him silly, telling him not to say things like that. The announcer says that round one was over with team three - Yaya, Kairi, and Hikaru - in the lead and announces the second round: the shouting contest where, depending on how loud your voice got, more points were given. Hikaru, with a bored expression, says that this round had nothing to do with flowers. Yaya says that this was her round, so Kairi asks if her loud voice was her specialty. She says that a baby's crying was a good move and that her volume would get higher if she Character Changed, so she calls to Pepe and fist pumps the air, only to knock over Hikaru's crepe. She apologizes, but tears are already coming out of the corners of his eyes and he begins to scream, causing Kairi and Yaya to shield their ears. Pepe and Musashi are also covering their ears and noticing that it was the same cry they heard when they had been fighting Easter.
The announcer says that round two also went to team three and tells them the next round: "Save the flowers! The big ducky race!" Yaya is in awe at the huge bicycle shaped duck while the rules are being called: each team will ride a bicyle; one person pedaling and the other person standing on the back cutting the marked balloons and asks which team would win the one thousand poppies. Yaya says that it seemed pretty impossible to win while Hikaru says that the name was "save the flowers," but they were cutting them. Kairi says that he was going to pedal the bike and that Yaya, calling her Ace, would cut the balloons, but Yaya gets mad and says that she wanted to pedal because that was what she was good at. She says again that she wanted to pedal and the announcer says that all the teams who were participating were to be at the starting line while Yaya and Kairi are looking at each other, Kairi saying "I get it." The race begins, the announcer saying that the first team was in the balloon zone and notices that the third team were nowhere to be found, but they appear and she says that they were in last place.
Kairi tries to reason with Yaya, calling her Ace, and says they should switch places because she couldn't do it, but she says that if she gave up that it would be uncool and that she was going to give her best so they could get the grand prize. When the announcer comments on the fact that the balloons were being popped very quickly, Kairi calls to Yaya, saying Ace, and she turns to him saying that Yaya was Seiyo Academy's Ace, meaning she had to work hard and try her best. She renders him speechless, but doesn't know it and tells him she was fine, saying he was good at cutting the balloon strings and to leave her to steering the bike. He smiles, as does Musashi, and tells her he understood. The announcer says that team three was finally in the balloon zone and that were amazing as they were cutting the balloons so easily. Yaya looks at Kairi and sees he Character Changed and was using a wooden katana and had a smile on his face.
Yaya is ecstatic that they had won the grand prize and agrees with Kairi who said that the ball would now be full of "yay" and "whee." She thanks the two for their help and Kairi says that the ball had a pretty color to it, causing Yaya to say that that was another tradition; having the Guardians each year give it a new color. He asks if she had made it herself and, with a smile, she says she had some free time over the winter break. Kairi says that was expected of the Ace, but before he could finish the word "Ace", he changes his mind and says "Yaya" before adding "senpai". She looks up at him surprised, with a blush and asks if he had just called her "Yaya". He says he had and she notices he put "senpai" on the end of her name. She smiles, but gets defiant again and says that adding senpai gave her name too many letters and that it had to be short, as "Yaya" was. He gets confused and so do Pepe and Musashi.
Kairi says that when the Guardians saw what was inside the ball, they would graudate with no worries and that the two of them would keep the Guardians going. Yaya asks about him saying the two of them and he says he hadn't said anything about it before because he wasn't sure and says that becasue of his parents' work, he would be coming back to Seiyo Academy. He asks her if he could get the Jack's Chair back and calls her Yaya-senpai. She yells "yay!" and says that he could, from that moment on. Hikaru joins in and says that it would be the three of them and holds up his heart's egg. One of them notice that his egg had a crack in it and he says that he was going to be a Guardian soon, too. Yaya and Kairi are surprised and the ending asks "will the egg break first, or will the ball break first. . .?" and says "there's just a little longer until the answer. . ." Pepe says she hoped that love and the egg were born soon to Musashi's confusion.