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.

A love-struck mermaid named Aquamarine supplies adventure and insights to two twelve-year-old girls, life-long friends who are spending their last summer together before one of them moves away.

Since cutting off her wings to save Never Land, Rani, a water-talent fairy, feels out of place with the fairies and wonders if she should live with the mermaids instead.

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.

Silver mermaids with golden hair go to sleep in the sea, counting fish instead of sheep.

When Pinkalicious and Peter go to the hidden cove to meet their friend Aqua, a mini-mermaid, they see pirates instead.

Once again Abby and her brother Jonah go through the magic mirror in their basement, and this time they find themselves interfering in the Little Mermaid story--and needing to set things right and make sure everyone has a happy ending.

Shelly is a princess! A real princess! It's been a well-kept secret in Trident City, but now the word is out, and Shelly doesn't know how to act! Should she start wearing a glittery crown? Or move to a grand undersea palace? Will her friends have to call her Your Highness? Being a princess may be exciting, but Shelly's not sure she can truly play this royal part.

Kitty helps her best friend Unicorn accomplish his dream of being a mermaid, but despite an elaborate DIY mermaid tail, the friends' trip to the beach does not go as planned and Unicorn's insecurities ermerge.

When a mermaid attempts to lure her into the sea, fourteen-year-old Adrianne, who lives in a superstitious island community, must choose between the promise of an underwater paradise and those she loves.