Hinako doesn't want to be saved. She wants Shiori to eat her, and the show understands that wanting to die isn't a plot device to overcome, it's a weight that doesn't lift just because someone shows up to love you. The mermaid stays anyway, and in that unbearable gap between two people where one is already gone and one keeps showing up, the show builds something quieter than hope, harder to name. The soundtrack arrives like breath, like the one thing worth staying conscious for, and every episode costs you something real.

Hinako lives alone by the sea, drifting through her days ever since an accident took her family into the ocean years ago. Around her one close friend, Miko, she keeps up a cheerful front, but alone she sinks into despair and dwells on vanishing beneath the waves. One summer, a deep-sea creature drags her under, and a mermaid named Shiori rescues her by killing it. Shiori then explains that she intends to eat Hinako, just not yet, and until that day she will stay close and protect her. The next morning Shiori joins Hinako's class as a transfer student, and Hinako finds herself hoping this girl can give her the end she has quietly longed for. Blending romance, horror and psychological drama, the story follows this unsettling bond between the two.