In the secluded countryside of Tottori, Nagisa Yamada, a pragmatic junior high student, strives to swiftly graduate and pave her independent path, her father long gone and her mother toiling in part-time jobs. Enter Mokuzu Umino, a cryptic transfer student with a melancholic aura, who asserts her mermaid origins and quest for a genuine companion before an impending storm. As their paths intertwine in Tottori, the duo forges an exceptional bond, navigating life's challenges together.