Within the Kanagawa prefecture lies the seaside city of Umineko. There, Okiura Kaname, a 2nd year high school student, attends Umineko Shougyou High School (or Umisho for short). He is also the manager of Umisho's swim team though he himself does not know how to swim. In fact, he is afraid of the water stemming from an incident which occurred some years ago.