Summertime is near! These novels for young readers and teens take place under the sea, on an island, in a treehouse and on a frivolous vacation.

"Deep Blue" by Jennifer Donnelly; Disney-Hyperion; 352 pages; $17.99.

This Disney project is mysterious and deep: a tale about mermaids for readers 10 and up. The mystical story stars six teenagers who are magical underwater creatures, but hope, dream, love and struggle to understand themselves and their roles in the world.

According to "Deep Blue," an evil force overtook the mythical Atlantis, but not before Merrow, the leader of the ancients, granted some lucky souls the power to breathe underwater and swim with magically infused tail fins. Once again, the evil forces threaten, but "The Mer" nations' only hope lives with these six teens — Serafina, Neela, Ling, Becca, Ava and Astrid — who form a sisterhood in order to save their worlds.

Part of a four-book project called the "Waterfire Saga," the ambitious "Deep Blue" will also have interactive, digital, video and music components. The second book, "Rogue Wave," will be released in January 2015.

Rich with themes of good and evil, self-discovery and empowerment, "Deep Blue" feels timeless and both magical and real. Mermaid and fantasy fans will fall in love.

"Of Neptune (The Syrena Legacy)" by Anna Banks; Feiwel & Friends; 336 pages; $17.99.

From the author of the best-selling "Poseidon" and "Triton," this young-adult novella tells the conclusion to the ongoing trilogy love story between half-human/half-Syrena Emma and her Syrena love Galen. The pair visits Neptune and is flung into being peacemakers between the ocean-loving Syrena and their land-dwelling counterparts. The power struggle threatens their ocean kingdoms.

A charming Half-Breed named Reed comes along as well. He can't hide his new feelings for Emma. With tons of action, romance and a luscious coastal setting, the classic merfolk myth is made mod, vibrant and even funny.

"The 26-Story Treehouse" by Andy Griffiths; illustrated by Terry Denton; Feiwel and Friends; 352 pages; $13.99.

Friends Andy and Terry live in a 26-story treehouse with a bumper car rink, skate ramp, mud-fighting arena, antigravity chamber, Maze of Doom and an ice cream parlor. Life is never boring, and the pair tells stories and has crazy adventures in this part-regular tale, part-graphic novel with lots of funny black-and-white cartoon sketches.

Completely wacky and fantastical, Griffiths' follow-up to "The 13-Story Treehouse" (same house, but they built up) is a kid-friendly (ages 8-12) tale that's too fun for words.

"The Summer Invitation" by Charlotte Silver; Roaring Book Press; 192 pages; $16.99.

Middle-grade girls will love this romantic, adventurous tale about two sisters who leave foggy San Francisco for a summer in New York City with their eccentric aunt. While the girls visit old-world locales, like Bemelmans Bar, and are schooled in how to act ladylike by their chaperone Clover, their sophisticated summer also includes first-love secrets about Aunt Theodora's past and understanding that great joy sometimes comes with great loss.

Penned with a vintage yet fun elegance, Silver's debut young-adult novel is exciting and lovely.

"The Islands of Chaldea" by Diana Wynne Jones and Ursula Jones; Greenwillow Books; 368 pages; $17.99.

Though the iconic author passed away before finishing the book, her sister, Ursula Jones, kept it alive, continuing the medieval magic of wizards, witches and supernatural animals. Riches are plenty in this vividly fluid journey about a girl named Aileen who embarks on a secret quest across the Islands of Chaldea.

With her magical Aunt Beck as companion, plus a mostly invisible cat, wise parrot and ragtag band of allies, Aileen sees her own magic bloom while rescuing her father and saving a lost prince.

Incredibly picturesque, with loads of Diane Wynne Jones' humor and insight, this exhilarating tale is sure to be a fabulously witty, fun classic.

"The Gollywhopper Games: The New Champion" by Jody Feldman; Greenwillow Books; 400 pages; $16.99.

The sequel to the popular tween novel "The Gollywhopper Games," this interactive follow-up, full of puzzles, riddles and challenges, introduces a new cast of boy and girl competitors. The kids once again battle for prizes in the Golly Toy and Game Company's competition, which was a huge success in the first book.

Two new brothers, an online video enthusiast and his overshadowing brother score high in regionals. Readers will cheer on younger Cameron to finally show the world he's not a nobody.

Great fun for puzzle addicts and reluctant readers, the nonstop action in Jody Feldman's tale is engaging.

To find out more about Lee Littlewood, and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate Web page at www.creators.com.