Tsukasa met a mermaid one day on the beach, who turned out to be a boy named Rui. Tsukasa became friends with him quickly and always came to the pier in the evenings to meet him in secret.

Tsukasa walked onto the beach and started looking around in the water for Rui. he bought him a small gift which was his favorite food

"Rui? where are you?" Tsukasa said with a calm voice. he walked a little on the shore so that his friend could notice him.