Aika Sumeragi, a high school student working as a C-Class salvager, finds herself with a new assignment: piloting the vessel of Eri Shinkai, the class president. After introducing Aika to the treasure hunting club and revealing coordinates …

Upon reaching their destination, Eri determined the treasure hunting club deserved respite and announced a beach party on a neighboring isle. Their solitude was short-lived; Aika found herself compelled to defend Karen against Eri’s teacher…

The series concludes with Aika, Eri, and Karen discovering a submerged airport, nestled in the ocean depths. Within the surprisingly operational facility, their exploration leads them to a revelation – the key to understanding Karen’s histo…