Would you trade your world for a soul?

Ever since the fateful day when the little mermaid risked everything for a human soul, merpeople have been under lockdown—absolutely no surfacing.

Sea princess Mairin bristles under the restriction and blames humans for her confinement. But when the kingdom comes under attack, the merqueen surprises Mairin by sending her to watch over a human they’ve secretly been protecting, the descendant of the little mermaid’s prince.

Feeling betrayed by her family, Mairin is all too ready to listen to the sea witch’s offer to redeem the little mermaid’s mistake and free her people. Using the sea-witch’s potion to gain legs and follow the human aboard the Titanic, Mairin sets out to complete the circle of unrequited love. If she can make the descendant fall in love with her, she will win back the freedom of her people.

But as she gets to know the humans, her heart changes toward them. Mairin realizes she has made a bigger mistake than the little mermaid ever did. Can she save the humans and her kingdom?