Two children set out to capture a mermaid, but she manages to escape all of their traps.

Uncovering an ancient evil, Serafina, a mermaid of the Mediterranean Sea, searches for five other mermaid heroines who are scattered across the six seas, to save their hidden world.

Neptune, King of the ocean, sends half-mermaids Emily and Aaron to the land of the midnight sun to investigate the source of the dangerous storms brewing in the ocean.

When young Pearl, a mermaid, becomes caretaker of a single grain of sand, she discovers that performing even the smallest task well can transform the world.

Aqua, the mini-mermaid, takes Pinkalicious and Peter to her favorite seaside spots.

"Astrid must confront her ancestor, Orfeo, the evil force behind the rise of the monster Abbadon, while Sera and her Black Fins train goblin troops for battle against her uncle Vallerio's death riders"--

Oona and her best friend Otto love to search for treasure...and often find trouble instead. Messy trouble. Tricky trouble. Even shark-related trouble. That's never stopped them before, though! After all, no proper treasure hunt is without some adventure. But when the grandest treasure yet is stuck in a deep, dark rift, Oona's not sure if she can dive right in. What might be waiting for her in those unknown waters?

Billy and his sister, Sheena, are visiting a tiny Caribbean island. It's the perfect place for an underwater adventure. There's only one rule to remember: Stay away from the coral reefs. But Billy can't resist the beauty of the reefs -- and he quickly discovers that he's not alone. Something that's half-human, half-fish is lurking deep below.

A desert mermaid living in an oasis seeks to save her people by rediscovering the forgotten songs of their ancestors.

The desert is no place for ocean-dwelling Kampii like Aluna and Hoku, especially now that Aluna has secretly started growing her tail.