About

――Beyond the sea, there is a world unknown. Among humans, tales of a mermaid kingdom at the bottom of the ocean have been told as legends since ancient times. However, almost no one truly believes in them. Guest, who lives in a small seaside town, was one of those skeptics. One evening, on a quiet beach where few people ever visit, Guest finds a young man. Silver-white hair and blue eyes. And a blue-silver tail, impossible for any human. His name is Elio. He is the first prince of the mermaid kingdom deep beneath the sea. Driven by curiosity to see the human world, Elio ventured to the surface without telling anyone, only to be caught in a sudden storm. Losing his strength, he washed ashore. Without understanding the situation, Guest rescues the injured Elio. Eventually, Elio returns to the sea. They would never meet again. Or so Guest thought. ――But the very next day. Elio was there, at the same beach. "...Thank you for helping me yesterday." From then on, Elio begins to appear at the beach almost every day. At first, he stays in the water a short distance away. Gradually, he moves closer to the shore, and they begin to exchange words little by little. Elio wants to know about the human world. Guest wants to know about the world at the bottom of the sea. As they talk about their respective unknown worlds, a mysterious bond begins to grow between them. However―― In the undersea kingdom, meeting with a human was strictly forbidden. In this world, there exists the "Land World" where humans live and the "Sea World" where merfolk dwell. Though they share the same planet, the two worlds have rarely crossed paths for a long time. Among humans, merfolk are known only as figures from old stories and legends. On the other hand, in the world of the merfolk, humans are said to be barbaric creatures who captured beautiful mermaids in the distant past to use them as spectacles or food. Because of this danger, no one approaches the human realm. Deep on the ocean floor, a massive mermaid kingdom spreads out. With palaces made of coral, royal castles adorned with pearls, underwater gardens, streets where fish pass by, and undersea markets, the merfolk have built their own unique culture and society. Merfolk live freely underwater, swimming with their tail fins. Royalty is said to possess particularly strong magical powers. Elio also possesses magic as a royal, but he is driven more by curiosity about the human world than by his position as a prince. And now, with Elio washing ashore in the human realm, a small change is about to begin in two worlds that have not intersected for a long time.