Living by the sea, protecting the sea, and journeying across the sea…They’re the BLUE MERMAIDS! Because of a shift in tectonic plates around 100 years ago, Japan lost much of its area to submergence. To preserve Japan’s territories, Coastal Cities sprung up, one after the other. Eventually, they became Marine Cities, and along with the expansion of sea-lanes to connect them, the need arose for a sizable staff to protect the seas. At the same time, maritime jobs were becoming more popular among women. Hence, the BLUE MERMAIDS had become every female student’s dream job.
Following Natsuki Enomoto's confession rehearsals with Yuu Setoguchi, their younger siblings Kotarou and Hina struggle to confess their own love. Despite a disastrous first meeting in middle school with her upperclassman Koyuki Ayase, Hina’s heart is captured by his warm smile. Initially confused by these newfound feelings, Hina soon realizes that she has fallen in love for the very first time. Chasing after her brother Yuu and her crush Koyuki, Hina also enrolls in Sakuragaoka High School; but the threads of love are far-reaching, and they entangle Hina and her friends. Boisterous but sensitive, Hina hopes to confess her feelings to the tender-hearted Koyuki. Meanwhile, Kotarou, oblivious to his own feelings for her, is determined to always keep Hina smiling. This movie follows Hina, Kotarou, and Koyuki in high school. Their youthful love forges new relationships, but also threatens to break others.
Love is blooming at Sakuragaoka High School. Natsuki Enomoto has finally mustered the courage to confess to her childhood friend, Yuu Setoguchi. However, in the final moments of her confession, an embarrassed Natsuki passes it off as a "practice confession." Oblivious to her true feelings and struggling with his own, Yuu promises to support Natsuki in her quest for love. While Natsuki deals with her failed confession, fellow classmate Koyuki Ayase struggles with his own feelings for Natsuki. Despite his timidness, he is determined to win over her heart. This movie follows Natsuki as she dreams of one day ending her practices and genuinely confessing to Yuu. Meanwhile, close friends also find themselves entangled in their own webs of unrequited love and unspoken affections.
