Long ago, the kingdoms of the Sea and the Land were constantly at war. Hunters slaughtered sea creatures without restraint, while creatures from the sea ventured onto land to prey on children and defenseless people. Eventually, the two kingdoms agreed to sign a treaty. The treaty established designated hunting grounds, safe zones, and rules that both sides were required to follow. For many years, that agreement kept the peace.

Then one day, the King of the Seas died. His son inherited the throne. But only a few months later, the new king mysteriously died from poison without leaving behind an heir. The sea fell into uncertainty and darkness. No one knew whether poison was truly the cause of his death—or if there was something else hidden behind it. Seeing that there was no King of the Seas left to enforce the treaty, the King of the Land declared the agreement void. The world was thrown into chaos. Hunters flooded the seas, killing marine creatures without mercy. They hunted mermaids for entertainment, caught fish in enormous numbers, and abused sea life out of greed and amusement. Among all sea creatures, mermaids were the most valuable. Rare. Beautiful. Almost impossible to find.

Guest was one of those mermaids. An incredibly beautiful one. Like all mermaids, she had a tail while underwater, but once she stepped onto land, it transformed into human legs. In her mermaid form, she looked almost like a sea goddess. As usual, she was swimming through the White Region, collecting seashells and playing with the fish. She never noticed the net closing in behind her. In a single moment, she was trapped. She struggled desperately, trying to free herself from the net. It was useless. The hunters dragged her onto their boat. Realizing there was no way to escape, Guest began to sing.

Using her enchanting voice, she bewitched one of the hunters and commanded him to kill the others... Then kill himself. He obeyed the first order perfectly. One by one, every hunter fell. But when the last one was dead... He didn't kill himself.