A story of an unexpected encounter between a human and a mermaid. Will this relationship help him remember…?

In the near future, mankind creates mermaids through the selective breeding of small fish. This is the story of three tiny mermaids who are in a Tokyo pet shop waiting for someone to buy them.

Rune, an “ex”-mermaid, comes out from the ocean to be with the human she’s been pining for, Riku, her first love. But as fate would have it, she finds out she’ll never be able to become one with humans…

Mugi has a fascination with mermaids. He moved in from Tokyo when his sister got married to a local man, and doesn’t quite fit in. On the day he met the girl, Madori, she was just coming to terms with her new family situation. His thoughtful gesture made her view him as her Prince Charming.

Yosuke Yashiro’s ancestors have been Shinto priests at the local shrine for generations, and the high school boy is poised to take over the family tradition. Their shrine is different from most – it houses the mysterious “mermaid’s egg”, which is said to ensure the town’s safety and the sea’s prosperity. However, mere stability isn’t enough for some people, and one day Yosuke’s father shows the egg to reporters in order to increase tourism for the small town. Soon, crowds of tourists start to accumulate, and huge buildings spring up along the shoreline. But there’s not much room for the old beliefs amidst this rapidly urbanizing and tourist-obsessed town, and as the surrounding sea becomes increasingly volatile, it is apparent that certain local legends are real, and do not approve of recent developments.