The Autumn Choral Competition, which is the early October activity held by the Aspertia Trainer's School for its second semester, is no ordinary choral competition. Rather, it is a showcase of vocal skills by both trainers and Pokemon. Also known as the 'Choral Battle', Pokemon must use sound-based moves such as Sing, Round and Echoed Voice, not only to match the songs sung by their trainers but also to attack the Pokemon in the opposing team.

Bianca reads the contest rules from the guidebook, and finds herself fascinated by this inventive form of competition. She glances over at the match-up chart, and sees that the 5 classes of A to E, each with 30 pupils, are split into groups of eight to ten and set to undergo rounds of elimination matches. She notices that Team Sawsbuck of Class C is exempt from the first round of elimination, and believes that it must be a top winner choice. She thinks it will be nice if the winning team comes from Class E, which is Cheren's class, and just then overhears Team Chatot from Class B reciting their motto.

WE WILL SURELY SURELY SURELY SURELY CONQUER THIS!!

Immediately, Bianca recalls how Black always makes a similar declaration, and tears quickly well up in her eyes. However, she wills herself not to cry, and thinks of White, who is clearly suffering from greater pain but never sheds a tear.

At that moment, a little girl approaches Bianca, and wonders if she knows where she may find students from Class E. Bianca laughs embarrassedly that she actually has no idea, but believes that someone nearby should know. She soon spots Leo walking by, and quickly runs over to the boy whom she recalls being in Cheren's class. Meanwhile, Leo is caught up in his worry that he would bring trouble to the group by being a tone deaf, and nearly chokes on himself when Bianca slaps him on the back to get his attention. He promptly recognizes Bianca as the person who gave Lack-two and Whi-two their Pokedexes, and Bianca hopes that he could help the little girl find her way. She turns to the little girl to ask who it is that she is looking for in Class E, and the girl reveals that she is searching for her elder brother, Hugh. In that instant, Leo sees her face, and immediately turns bright red with embarrassment while stammering incomprehensible words.

Soon, the Choral Competition begins, and the Announcer calls for the first two competing teams to go on stage, which are Team Swablu from Class A and Team Tympole from Class B.

Team Tympole: Oh bathe us here, Echoed Voice~ Lalala, carry out voices far~!

Team Swablu: The soft clouds that float in the quiet sky~ (the soft clouds that float in the quiet sky~) Just like cotton candy~! (just like cotton candy~!)

The Announcer marvels at how well Class B is performing their title song 'Carry our voices', and finds it convenient that the lyrics directly command the move 'Echoed Voice'. On the other hand, Class A also sings beautifully with 'Cotton Candy', which the Swablus echo by using the move 'Round'. He notes that by the end of the first verse, two of the Tympoles have been knocked out by 'Round', while all the Swablus have managed to stand their ground. The match goes on, and as both teams wrap up their songs with determination and eagerness, the Announcer states that it is time to score each team based on the trainers' song, Pokemon moves, their precision as well as harmony. He invites everyone to welcome their special judge, Roxie, who is also the Virbank Gymleader, and the girl fervently jumps on the table to greet the crowd, causing the Announcer to sweatdrop. Roxie announces that the winner of the first round goes to Team Swablu of Class A, and the room immediately roars with cheers and applause.

At the back stage, Yuuko gasps that it is the real Roxie, and Yuki finds it unbelievable that a professional musician has agreed to be a judge at their school's choral competition. Mayu wants to know if Whi-two really went to see Roxie in person with Lack-two the night before, and Whi-two reveals that although she didn't really know how it happened, Lack-two indeed became quickly acquainted with Roxie after her concert and easily convinced her to come, not only for the Choral Competition but also for the upcoming Cultural Festival. Yuuko thinks Lack-two must have done this after overhearing their wish to invite Roxie to their events, and all three girls swoon over how great Lack-two is. Hearing that, Whi-two realizes that Lack-two shows kindness to everyone around him and the way he treated her was nothing special. She thinks it is for the better that she returns the telescope to him since she doesn't really have any reasons to accept it, and Foongy agrees with a nod.

At that moment, the second round begins on stage, and Yuuko exclaims that they will be up next. Yuki demands to know where the boys are, and Lack-two shows up apologetically with Leo ad Hugh, the former still blushing and the latter unusually quiet. The girls yell at Hugh for still not getting his costumes on, and to their utter shock, he replies with a simple 'sorry'. Yuki, Yuuko and Mayu instantly pull back in fear, and cannot believe that Hugh actually apologized. They think that something bad is about to happen, and Hugh is ready to break into a fury at their mockery. However, Lack-two holds him back, reminding him that she will overhear him, and Hugh immediately keeps his mouth shut while trying to suppress his emotions. The girls wonder who Lack-two is talking about, and follow his gaze to see a young girl sitting among the audience next to Bianca. They realize that it is Hugh's little sister, and promptly understand that Hugh is trying to play the role of a good brother who treats girls nicely. Feeling superior, Yuki, Yuuko and Mayu agree to play along if Hugh says 'please', and Hugh, despite his unwillingness, drops his head and mutters a 'please' while cursing the girls under his breath.

Yuuko then turns to Leo and wonders what his problem is, and Yuki says he is clearly infatuated. After all, Hugh's little sister, unlike her brother, is extremely cute and adorable. Hearing that, Hugh explodes into fury and demands to know if Leo has his eyes on his sister. Leo quickly denies by making a series of incomprehensible sounds, which to the girls' utter surprise, are unexpectedly pleasant to the ears. Yuki thinks they might have a winning chance with this singing voice of Leo, and everyone proceeds to gear up by pulling on their Jigglypuff hats.

Soon, the third round commences, and the group is called on stage as Team Jigglypuff of Class E, up against opponents coming from Class A. Thanks to the altered voices of an unusually restrained Hugh and an extraordinarily apprehensive Leo, the group manages to beat opponent after opponent, and eventually enters the final match against Team Sawsbuck of Class C, which is the top winner choice. The Announcer muses that, with the beautiful and harmonious 'Grass Whistle', Team Sawsbuck has not only hypnotized their opponents but also the audience and the judge. On the other hand, Team Jigglypuff, despite not being highly rated at the beginning, progressed with such an amazing streak that even their class teacher, Cheren, is genuinely shocked.

Gathering with his teammates, Lack-two states that although they have won with 'Sing' all along, the same strategy may not secure their chance against the next opponent. He proceeds to ask for rhythm instruments from the staff before the match begins, and the Announcer wonders what they have planned since no one is actually holding anything as they step on stage. He explains to Roxie that candidates are allowed to use musical instruments ranging from the piano, guitars, triangles, castanets or even tambourines, and is confused as to what Team Jigglypuff has chosen.

Team Sawsbuck: We have gone through a cycle of spring, summer, autumn and winter again~! Accompanied by the sounds of grass~!

As soon as Team Sawsbuck begins singing, the 'Grass Whistle' from their Sawsbucks instantly overwhelms Team Jigglypuff. Everyone struggles to keep their eyes open, including Roxie and the Announcer, who questions if they can really last until the end of the song. Suddenly, the loud clap echoes across the hall, waking everyone, and they see that Dewott has started to create a beat with its scalchops. Immediately, Team Jigglypuff begins to retaliate, and sings their song with all their might.

Team Jigglypuff: I hope you will look over here once more~ I hope you start over again from your dream~ The dream that calls upon your courage~

Roxie exclaims at how well Dewott is clapping with its scalchops, and thinks it not only wards off their sleepiness but also strengthens the rhythm of the song. The Announcer is amazed by how the two teams fight each other with 'Grass Whistle' and 'Sing', and Lack-two thinks it is time to enter the next phase. With a nod, Mayu gestures to the Jigglypuffs, and as the team does their next line, the Jigglypuffs unleash a powerful Hyper Voice, knocking over the piano as well as the opposing Sawsbucks. The Announcer cries out in astonishment at the scene, and states that the Sawsbucks have fainted, drawing an end to the match and making Team Jigglypuff of Class E the champions of their competition. The crowd immediately breaks into a roaring cheer, and Cheren bolts right up in disbelief as Bianca and Hugh's little sister rejoice at the announcement.

Later, Roxie still has trouble containing her excitement, and once again congratulates Team Jigglypuff for their victory. She would like to thank them for giving her such enjoyable music, and decides to present to them the special judge's prize, which is the entry right to the 'Unova Choral Competition', held at Castelia City in one week's time. Yuki, Yuuko and Mayu are overjoyed that they are visiting Castelia, and other students in Class E start to protest that it isn't fair to invite Team Jigglypuff only since everyone has been cheering and supporting them. Roxie grins that she shall invite the entire Class E in that case, and Cheren thinks he needs to bring it up for discussion at the staff meeting. However, Roxie tells him not to worry about the cost or anything since she and her father would handle it all. She reveals that her father is the captain of the ferry that runs between Virbank and Castelia, and also has quite a lot of connections with the travel agency. Moreover, her band's agency also has its connections and she shall put that to good use. With that, she gives Lack-two and Whi-two a big hug, hoping that she may repay them that way, and Yuki, Yuuko and Mayu wonder what the two could have done for Roxie. As for Lack-two, something glitters in his determined eyes, and he knows it is time for business again.

On the day that Class E departs for Castelia, everyone gathers at the port at Virbank City, and Roxie fervently introduces her father to them. She points out Lack-two and Whi-two from the crowd to her father, and the man excitedly runs over to shake hands with them, his enthusiasm startling Whi-two. Lack-two thanks him for his hospitality, but Pop Roxie tells him not to make a big deal about it. He ushers them to get on the ferry as it shall depart soon, and addresses the two as Dewott Boy and Foongus Girl, clearly having seen their performance at the Pokestar Studios.

Soon, the ferry begins to sail off, and Lack-two makes contact with Looker, who is following them on his canoe from behind with Croagunk. Lack-two informs him that they have set out successfully in the name of a school activity, and wants Looker to meet him at the Sewers once they arrive at Castelia City. Looker is surprised to learn that Castelia has sewers, and Lack-two explains that its entrance is near the Skyarrow Bridge at the Thumb Pier. Looker wants to know if it is where the Sage hiding at Castelia is, and Lack-two reveals that they are actually dealing with two Sages this time, Bronius and Ryoku, whom they must ensure successful capture on this trip to Castelia…