Centuries ago, the sorrow of a spurned mermaid cursed the ocean. Now the fate of the sea rests on the shoulders of her great-nephew, Prince Caspian of Atlantis. Upon inheriting his ancestor's magical voice, he is also entrusted with breaking her curse by finding true love with a human. But Caspian doesn't believe love comes at the swish of the tail, at least, not until he meets oceanographer Stefan Firth.

In spite of the bond that forms between them from the beginning, Stefan's skepticism and his heartbreak over a lost love keep him from even considering a relationship with Caspian. Caspian has no choice but to follow the path his great aunt once did and resort to the Sea Witch's assistance. He must help Stefan love again if he is to break the curse and bring them their fairytale ending.