Ariel is a beautiful mermaid princess with an even more beautiful voice, who just happens to be enthralled with the human world so much that she disobeys her father to visit the surface. When she rescues a handsome prince from drowning, the sea-witch Ursula recognizes an opportunity to tempt the naive girl and overthrow the kingdom at the same time.

Sweet, awkward sixteen-year-old Ruby Gillman is desperate to fit in at Oceanside High, but she mostly just feels invisible. She's math-tutoring her skater-boy crush, who only seems to admire her for her fractals, and she's prevented from hanging out with the cool kids at the beach because her over-protective supermom, has forbade Ruby from ever getting in the water. But when she breaks her mom's #1 rule, Ruby will discover that she is a direct descendant...

Lumina is a mermaid who dreams of being a princess. As long as she can remember, she's had a magical power that makes pearls dance and glow. Lumina and her best friend Kuda, a pink seahorse, embark on an adventure to a majestic mer-kingdom. There, she uses her powers to help her friends prepare for the Royal Ball. Lumina then discover that her magical pearls are the key to unlocking her true destiny and ultimately saving the kingdom.