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

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.

When Neptune tells Emily and her merman father and human mother to return to Brightport to try to make merpeople and humans work more closely together, Emily faces problems with old enemies, her new, half-merfolk friend Aaron, and a mystery related to a group of legendary lost sirens.

Emily Windsnap doesn't know how to swim. Her mother has always cautioned her to stay out of the water. But it's hard to make friends at the beach when everyone else is having fun in the waves! So when swimming lessons start at school, Emily is excited to finally have the chance to learn. Standing beside the pool, she feels the water calling her, but when she jumps in, she gets a strange, kind of scary sensation ... like her legs are stuck together....

Learn about mermaids and why they were believed to be real.

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...

On Mermaid Day, the mer-queen throws a big bash and sea creatures of all kinds attend, including a shy shark who joins in the dancing.

Lucas and Clara are floating on a raft when a wave casts them into the sea, where Lucas catches a glimpse of a coral kindom and a dark-haired mermaid helps him, but when his father, King Caleb, hears of this, he scolds Lucas and tells him he has broken an age-old pact.

A little sea princess, longing to be human, trades her mermaid's tail for legs, hoping to win the love of a prince and earn an immortal soul for herself.