In the coastal town of Bristol Cove, ancient mermaid legends become a dangerous reality.

Entertainment · Published 3 October 2026 Swipe more like this →

In short: When a mysterious young woman named Ryn arrives in a small fishing town, she triggers a series of events that expose the existence of merpeople. As marine biologists and locals uncover the truth, they find themselves caught in a primal struggle between humanity and an ancient, aquatic species fighting for survival.

The series centers on Ryn Fisher, a mermaid who emerges from the ocean to search for her abducted sister, Donna. Her arrival disrupts the quiet life of Bristol Cove, Washington, a town with a long history of mermaid folklore. As Ryn navigates the human world, she forms complex bonds with marine biologists Ben Pownall and Maddie Bishop. These relationships are complicated by Ryn's siren song, a defense mechanism that exerts a hypnotic, often obsessive influence over humans, creating a significant emotional and psychological burden for those she encounters.

As the narrative progresses, the conflict expands beyond a single search. Pollution and industrial activity, such as sonic waves from oil rigs, drive more merpeople to the surface, escalating tensions. By the third season, the threat shifts from military experimentation to an existential war led by Tia, a mermaid tyrant seeking to unite various colonies to eradicate humanity. The survival of the species becomes tied to Ryn’s daughter, Hope, whose birth through a surrogate highlights the desperate measures taken to ensure the future of their kind.

The show also explores the blurred lines between species through the Pownall family history and the existence of hybrids. Characters like Helen Hawkins discover their own ancestral ties to merfolk, revealing that human and mermaid bloodlines have intermingled for centuries. This genetic legacy, combined with the use of mermaid stem cells for healing, creates a world where the boundary between human and sea creature is increasingly porous. Ultimately, the series examines the consequences of human greed and the violent cost of coexistence, culminating in a final battle that forces a new leadership upon the merpeople tribes.

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