The Little Mermaid lives in an underwater kingdom with her widowed father (Mer-King), and her five older sisters, each of whom had been born one year apart. When a mermaid turns fifteen, she is permitted to swim to the surface for the first time to catch a glimpse of the world above, and when the sisters become old enough, each of them visits the upper world one at a time every 365 days. As each returns, the Little Mermaid listens longingly to their various descriptions of the world inhabited by human beings.