In this series the chapters were inspired by famous paintings. Chapter 6 was based on Water Serpents I by Gustav Klimt.
Identical twin sisters visit Port of Nagoya Public Aquarium. But one of them will also be going to the same aquarium on a date with her girlfriend from university. The other twin overheard those plans and is feeling rather sour about it.
Each chapter ends with an explanatory page. When talking about chapter 6 and the imagery of Klimt's painting, Mimoto notes how common aquarium dates are in yuri.