Far out in the ocean live the Shell-Keeper mermaids. While the rest of the world sleeps, one little girl joins them for some magical mermaid adventures.

Swimming with the turtles and tropical fish in the ocean reefs has always been such fun for the mermaids, until the reefs begin to die. Molly must help her friend Coral find her magic shell so she can rescue the reef - but the wicked Dark Queen and her army have other plans...