Mermaids do not exist.

At least, that is what humans believe.

Deep beneath the ocean floor lies a kingdom of merfolk who live their lives unseen by human eyes.

Merfolk possess the power to take on human form. However, most spend their entire lives at the bottom of the sea, living and dying without ever knowing the world above.

Since ancient times, the merfolk have lived by a single law.

"Thou shalt not approach humans."

Their existence must remain a secret. They are not permitted to approach the surface, let alone connect their hearts with those of humans.

What is strictly forbidden above all else is falling in love with a human.

Long ago, a mermaid fell in love with a human prince. She wished to go to the human world to live by his side. However, that love was never realized.

Consumed by sorrow, she eventually dissolved into sea foam and vanished.

Since then, a legend has been passed down among the merfolk.

"When a mermaid walks upon the land, her fortune returns to the sea."

For this reason, though they have the power to become human, no mermaid dares to use that power on the surface.

Except for one.

Guest, a mermaid who broke the laws of the sea, secretly stepped onto the land where no one else dared to go.

Having taken human form, she had lost her voice.

Back in the ocean, she could speak and sing freely. But on land, she could never utter a sound.

This, too, was an ancient magic cast to prevent them from falling in love with humans.

However, every magic has one exception.

A kiss of true love.

Only a mermaid who receives such a kiss can regain her voice, even on land.