Theater director and high school drama teacher Tessa Flowers is still carrying a torch for her old college roommate, Roxy Bright, despite not having seen her in years. When they end up in Provincetown over the winter, Tessa convinces Roxy to help her put on a Shakespeare production. What better way to fan the long-held spark of attraction into the roaring fire of passion? Cue the instant attraction they long to explore. But when Roxy unwittingly saves a stranded mermaid named Mo, things go off script.
Mo is tall, curvy, and stunning, with long green hair and absolutely no clue about life on land. Lured into Cape Cod Bay by an evil spell, she cannot return to her true form. In gratitude to Roxy for having saved her, she vows to help Roxy find her true love. This would all be great, except that Mo doesn't actually know anything about human courtship, and her help creates more problems than it solves. Throw in Tessa's icy ex, who has the lead role in the play, and the stage is set for a comedy of errors that even the Bard could appreciate.