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.

While concentrating on her goal of becoming popular, including hiding her eccentric family from the cool crowd, thirteen-year-old Molly discovers that she and her older sisters are half human, half mermaid.

Half-mermaid Molly Seabrook's usual woes--an embarrassing family, lying to her best friend, keeping her nemesis quiet--are compounded when twin merfolk arrive from Meire with an agenda.

While riding the subway home from the pool with his abuela one day, Julián notices three women spectacularly dressed up. Their hair billows in brilliant hues, their dresses end in fishtails, and their joy fills the train car. When Julián gets home, daydreaming of the magic he's seen, all he can think about is dressing up just like the ladies in his own fabulous mermaid costume: a butter-yellow curtain for his tail, the fronds of a potted fern for...

"As the full moon rises, we meet the lively, lovely mermaids and a breathtaking array of oceangoing friends, from turtles and seals to whales, octopi, polar bears, and many more. And here come the mermaids' cousins-the adorable selkies and the fairy-like nymphs! Meanwhile, Her Majesty the Merqueen keeps watch over them all. Readers curious about mermaid habits and anatomy will love diving into the Mermaidology facts that follow the story. And if you...

Alina worries as her grandmother's memories fade, but when she meets a mermaid who takes her on an adventure everything changes.

On her seventeenth birthday, Tempest must decide whether to remain a human and live on land or submit to her mermaid half, like her mother before her, and enter into a long-running war under the sea.

"Traveling home by cruise ship should be a relaxing break after Emily's latest adventure, but things take a turn when the ship is overtaken by a pirate king and his crew. After the pirates collect everyone's riches, they steal something even more valuable: Aaron. The pirate king's eldest son takes Aaron captive, forcing him to help guide the pirates to the mythical Trident's Treasure. So Emily dives into action and joins the younger son's crew in...

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.

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.