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.