Siren

As an old friend visits Helen, a new mermaid arrives.

Another mysterious death is uncovered in Bristol Cove.

Ryn learns the secret existence of her unborn child.

Ryn helps her surrogate through delivery.

Ryn returns to land to explore human motherhood. Maddie and Robb come across a gruesome discovery. Ben experiences mysterious side effects, and Ted confronts Helen.

Ryn discovers a refuge of injured mermaids.

Ryn, Ben, and Maddie must recruit new allies.

Ryn, Ben and Maddie must protect Bristol Cove.

Tia unleashes a deadly attack on Bristol Cove.

An undersea battle ensues between the mermaid tribes.