Takamine Ruka (aka Takaruka/Kaki Haruka) and Seto Ruka (aka Setoruka/Tsutsui Ayame), who attend the local Nozomigaoka High School, have always been together since childhood, so they are called "Ruka Ruka" by those around them. One day, in her third year of high school, still a member of the after-school club, Ruka Ruka finds a classroom decorated with sweets in the back of the school building. She is invited inside and discovers that it is the plastic model club, which is on the verge of being disbanded! The two decide to make plastic models at the urging of their advisor, Mr. Yomota, aka Yomo-san (Okada Yoshinori)...

One day off, Seto Ruka (Tsutsui Ayame) is stranded with a broken bike when a female rider appears in front of her. The moment her eyes meet the bike's headlights... a gentle breeze blows through Seto Ruka's heart! In an instant, Seto Ruka becomes captivated by bikes. The next day, Taka Ruka (Kaki Haruka) notices that Seto Ruka is acting strangely. Seto Ruka is holding a bike magazine in his hand... Meanwhile, Yomo-san (Okada Yoshinori) tries every trick in the book to get Taka Ruka to join the plastic model club, but...

Taka Ruka (Kaki Haruka) and Seto Ruka (Tsutsui Ayame) successfully join the Plastic Model Club! Just when it seems the club has escaped the threat of being disbanded, a shocking truth is revealed: the club will be disbanded if it doesn't find three new members! The Plastic Model Club is once again in a pinch, and Seto Ruka searches for one more member to save them. At that time, the two of them set their sights on Wataru (Yamazaki Ryutaro), a member of the After-School Club. However, it's difficult to persuade Wataru, who has a certain situation, and a fight breaks out between Taka Ruka and Wataru...

歌を口ずさみながら、花壇の花に水をあげているセトルカ(筒井あやめ)。その歌声を聴いた軽音部の遠藤類から、バンドのボーカルをしてほしいと頼まれる。タカルカにバレないようにバンド練習をするセトルカは、プラモ部を休むようになる。何か隠している様子のセトルカに対して、タカルカ(賀喜遥香)はやきもきしていて…。そんな中で迎えた軽音部の定期演奏会当日。果たして、類との出会いでセトルカの心に芽生えた小さな恋の結果は…！

よもさん(岡田義徳)が外れくじを引いたことにより、プール掃除の担当となってしまったプラモ部。少ない人数ではプール掃除が終わらないと危惧し、セトルカ(筒井あやめ)は軽音部、タカルカ(賀喜遥香)は玲(小林桃子)に助けを求めるも撃沈してしまう…。 そんな中、よもさんが発案したのは、部活対抗カーレース！負けた部活がプール掃除を行うというルールのもと、他の部活を巻き込んで真夏のプールレースが開幕！