Five years ago, nineteen‑year‑old Maren Farrow, a mermaid descendant, has been working as a waitress at a seaside restaurant to support herself since her mother Brynn Farrow (also a mermaid) passed away. One day, while secretly watching her longtime crush—the charming lifeguard Ryker Colton—on the beach, Ryker’s girlfriend, heiress Tatum Prescott, humiliates Maren in the restaurant, calling her a poor nobody and warning her to stay away from Ryker. At that moment, thirty‑one‑year‑old Declan Vance, a sexy and handsome dock repairman (formerly a marine biology research captain), walks into the restaurant and helps Maren out of the awkward situation; they accidentally kiss, and instantly Declan realizes that Maren bears an uncanny resemblance to his first love—the mermaid who saved him in a shipwreck five years ago, who is none other than Maren’s mother, Brynn. That night, Declan stumbles upon Maren’s secret by the shore: her legs transform into a mermaid tail upon contact with seawater. Because of his lingering feelings for Brynn, he decides to keep Maren’s secret and offers to help her understand her mermaid abilities, accept her identity, and become confident enough to win Ryker’s affection. But over time, Maren and Declan grow to love each other, and together they uncover the truth behind the shipwreck from five years ago.
