Gertie the Mermaid is a little girl just like any other. The only difference is that she has a tail, and lives in the sea.
Our story begins on the night before Gertie's birthday. Mumma Mermaid tells Gertie that she'll be allowed to swim a little further out now that she's older, and she gives her daughter some excellent advice about how to stay safe when exploring along the coastline.
Gertie, however, has other ideas, and decides to ignore her mother's wise words. Soon she is having the biggest adventure of her life as she is chased down the river by land folk, and finally gets caught up in a fishing net.
Luckily Gertie comes through it all safely and gets home just in time for her birthday party to begin.