Summer has an amazing job as a mermaid. All of her hard work and training pay off when she saves her crush, Lucas, from drowning. She finally has his attention but her cousin, Cassidy, doesn't want Summer to be happy. Cassidy has always wanted what Summer has and now she wants Lucas. Just when life is starting to look good for Summer and Lucas, Cassidy ruins everything for Summer, driving a wedge between her and Lucas. Will Summer be able to prove Cassidy is up to no good, and keep Lucas from falling for her, or will Summer lose him forever?