The series plot is centered on a mermaid, Nikki, who is rescued by a young man when she washes ashore in Miami. Her savior, Matt Johnson, is a lawyer living with a roommate and engaged to the daughter of his boss. Initially, he is in utter disbelief of Nikki's nature, until it is proven true. According to the series mythology, mermaids are a race of creatures whose evolution took place underwater. The mermaids originate from a sunken city and have supernatural abilities, including superhuman strength and agility, as well as being able to see in the dark, read emotions and have a connection with other sea creatures. However, another race of creatures who began their existence underwater, but have since adapted onto dry land, include Eric Luger who is hunting Nikki. Nikki, meanwhile, attempts to enact a normal life by working as a waitress at a local restaurant while living with Matt and his roommate. She begins assisting Matt in his attempts to help people: as the villainous Luger assesses, mermaids are drawn to protecting the innocent, it's "in their blood" (much like witches).
During the casting process, Kern "looked in London and New York and New Zealand, Hollywood, Florida, Melbourne and Sydney" and, after interviewing around 300 people, discovered "a fresh new face" in Australian Nathalie Kelley who played the lead role of Nikki. Geoff Stults was then cast as Matt, and Roger Daltrey as principal antagonist Luger. Brandon Quinn, who later went on to play Homeland Security Agent Murphy in Charmed's eighth season, played Matt's "goofy best friend" in Mermaid. Quinn spoke of his roles in both series:
"[In Mermaid] I was the party man... in the pilot, I had no job; I was a permanent bachelor. And when Brad [Kern] told me about [Agent Murphy], he was, like, 'He's a Homeland Security agent, he's 180 degrees opposite from what you played in my pilot this year, but I really think you could do it.' And I was, like, 'Wow, thanks for trusting me with Agent Murphy."
Additionally cast in main roles were Ana Ortiz (who went on to star in Ugly Betty) and Beatrice Rosen who, along with Quinn, developed a recurring role in Charmed's eighth season as Maya Holmes, an innocent whose image Piper Halliwell inadvertently uses as her false identity 'Jenny Bennett'.
Reasons For Not Getting Picked Up
The pilot was considered to have a good chance of being picked up, but when The WB and UPN merged into The CW, the resulting network passed on the show. Speaking on the failure of the series to be picked up, Kern also revealed that the studio Paramount/CBS "decided at the last second to cut the budget in half", which resulted in the number of shooting days to be reduced, thus decreasing the quality of the pilot in being able to "'sell' the concept".