When she incurs Neptune's wrath by finding a diamond ring buried under rocks in the ocean, Emily is put under a curse that will force her to choose to be either a mermaid or a human and split up her parents forever.

Of all the creatures in the ocean, sea horses are Echo Reef's favorite. They're sweet and gentle and they glide through the water so gracefully. When Echo discovers that Rocky Ridge, one of her Trident Academy classmates, has his own pet sea horse, she wants one right away. Not everyone agrees sea horses should be pets, however. Perhaps they are happiest when swimming freely. But Echo thinks that if Rocky can make a sea horse happy, she can too! Can't...

"Mermicorns Serena and Lily try to use simple invisibility magic while doing a school project about magical mistakes, and learn a powerful lesson about using magic responsibly."

"For as long as she can remember, twelve-year-old Emily Windsnap has lived on a boat. And, oddly enough, for just as long, her mother has anxiously kept Emily away from the water. But when Mom finally agrees to let her take swimming lessons, Emily makes a startling discovery -- about her own identity, the mysterious father she's never met, and the thrilling possibilities and perils shimmering deep below the water's surface. In a lovely twentieth-anniversary...

"Not one of the merkids in Shelly Siren's third-grade class can believe the shell-shattering news: 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...

New to Lady Sealia Foam's Mermaid School, Marnie Blue worries about fitting in and doing the right thing when a classmate is in danger.

"Ariel loves to play make-believe-- especially when she pretends to marry the prince of her dreams!"--P. [4] of cover.