Hiram Bernard's twenty-five year old daughter is missing. Hiram contacts the police, but in a world inhabited by both humans and supernaturals, the police don't always want to get involved. They send Hiram to Low Campbell, ex-cop, private detective, and mermaid, Hiram's reluctant to turn the job over to a mermaid until Low convinces him that she's a little more dangerous than the mermaids you see in the movies.
Low's search for Hiram's daughter takes her to a club called the Glass Box, which turns out to be owned by a supernatural, a supernatural who turns out to be a bogeyman. The bogeyman refuses to release Hiram's daughter, forcing Low to show him why the vampires and werewolves refer to her kind as dirty little mermaids.