Middle school student Kon Chigawa has never left the small island where she was born, nor does she expect to. Loneliness is her constant companion, and love is a completely foreign concept to her.

That is, until she encounters city girl Furuka on a cliff—and ends up resuscitating her after they fall into the ocean! When they regain consciousness, the two find themselves in front of a cave said to be the home of a fearsome monster.

Little do they know that their chance meeting will set a series of strange occurrences in motion on this mysterious island…