After her mother unexpectedly dies, Selima is forced to live with her estranged father in Las Cuevas Bay. Being the newcomer whom no one knew existed, she spends most of her time exploring by herself. While in the forest, she stumbles upon an extraordinary secret that has been hidden for hundreds of years … there is a mystical river, inhabited by merfolk.
Selima is befriended by a beautiful mermaid name Draya. Her life becomes challenging when she and the mermaid’s fiancé, Amarus, fall in love. From then on, Amarus guides Selima in a plan to bribe the Sea King, who is the only one who can grant him legs.
Both Selima and Amarus are very naïve. Their desire to be together has tangled them in a predicament that neither can handle. Selima is at risk of destroying the progress she and her father have made in repairing their relationship, and her stepmother has become suspicious of her daily whereabouts.
An old woman from the village helps Selima in spite of her knowledge of the potential consequences if merfolk and humans were to mingle in any way. However, no one is prepared for the trickery of the Sea King or the price of breaking Draya’s heart.