It's already spring-time in Kitansanriku, and a new school year has started. Aki is now a senior in high school. Thanks to the success of the opening day of the parlor train, Yui and Aki by now are the most popular high school girls in Iwate. Aki looks up at their billboard, seemingly happy recalling those times with Yui. Fans are still going to the station. They are told they can still see Yui every Saturday at the station. But with Aki... As Daikichi had promised Haruko, Aki's PR activities for the train have stopped and she's back to being a normal high school girl. However... At the Diving Department, Isono is nervous to be having more girls enroll in his class. "I've never taught with girls in front of me!" Aki: "I'm a girl!" Isono: "I don't think of you as a girl!" Isono, boosting up his confidence, comes in his class but the girls are more interested in Aki. "Here she is!" One of the girls trick her into saying "Jejeh" by pretending there's a cockroach.
お座敷列車イベントの成功で、アキ（能年玲奈）とユイ（橋本愛）は、地元では誰もが知る有名人になった。そして、アキは春子（小泉今日子）との約束を守って活動を休止し、いつもの高校生活に戻る。漁協では、さらに観光客を呼び込もうとミーティングが開かれた。アキのユニークなアイデアに、海女クラブ全員が大乗り気！ そのアイデアとは…。一方、ユイは謎を秘めた水口（松田龍平）に詰め寄り、その正体を暴こうとする。
