Annette Kellerman, the Australian swimming star of the early 1900s, made a number of films, most of them in the 1910s, which displayed her athletic skills. Most of these films were underwater fantasies, and this one was no exception. Here, Kellerman is Merilla, a mermaid who is the "Queen of the Sea." Not satisfied with being a mermaid, she wants a mortal human body with an immortal soul. She discovers she can achieve this if she saves four human lives.