Above World Series by Jenn Reese, Kate Rudd

Thirteen-year-old Aluna has lived her entire life under the ocean with the Coral Kampii in the City of Shifting Tides. But after centuries spent hidden from the Above World, her colony’s survival is in doubt. The Kampii’s breathing necklaces are failing, but the elders are unwilling to venture above water to seek answers. Only headstrong Aluna and her friend Hoku are stubborn and bold enough to face the terrors of land to search for way to save their people... moreThirteen-year-old Aluna has lived her entire life under the ocean with the Coral Kampii in the City of Shifting Tides. But after centuries spent hidden from the Above World, her colony’s survival is in doubt. The Kampii’s breathing necklaces are failing, but the elders are unwilling to venture above water to seek answers. Only headstrong Aluna and her friend Hoku are stubborn and bold enough to face the terrors of land to search for way to save their people. But can Aluna’s warrior spirit and Hoku’s tech-savvy keep them safe? Set in a world where overcrowding has led humans to adapt—growing tails to live under the ocean or wings to live on mountains—here is a ride through a future where greed and cruelty have gone unchecked, but the loyalty of friends remains true. less

A thrilling sequel from an exciting new voice in middle-grade sci-fi tracks two ocean-born children braving the dangers of the Above World.The desert is no place for ocean-dwelling Kampii like Aluna and Hoku, especially now that Aluna has secretly started growing her tail. But the maniacal Karl Strand is out to conquer the Above World, and the horselike Equians are next on his list... moreA thrilling sequel from an exciting new voice in middle-grade sci-fi tracks two ocean-born children braving the dangers of the Above World.The desert is no place for ocean-dwelling Kampii like Aluna and Hoku, especially now that Aluna has secretly started growing her tail. But the maniacal Karl Strand is out to conquer the Above World, and the horselike Equians are next on his list. Aluna, Hoku, and their friends — winged Calli and Equian exile Dash — race to the desert city of Mirage, intent on warning the Equians. When they arrive, Strand’s clone, Scorch, has gotten there first. Now the Equian leader has vowed to take all his people to war as part of Strand’s army. Any herd that refuses to join him by the time of the desert-wide competition known as the Thunder Trials will be destroyed. To have any chance of defeating Scorch and convincing the Equians to switch sides, the four friends must find a way to win the Trials. The challenge seems impossible. But if they fail, the desert — and possibly all of the Above World — will be lost to Karl Strand forever. Here is the action-packed follow-up to Above World, which Kirkus Reviews called "a thrilling sci-fi adventure. Imaginative and riveting." less

In this third and final adventure in the Above World series, Aluna and her friends finally face their most terrifying enemy, Karl Strand.Aluna and Hoku, Kampii from the City of Shifting Tides, and their friends, Equian Dash and winged Aviar Calli, are determined to stop a war. The maniacal ex-scientist Karl Strand is planning to conquer the world with his enormous army of tech-enhanced soldiers . . . unless the four friends can get to Strand first... moreIn this third and final adventure in the Above World series, Aluna and her friends finally face their most terrifying enemy, Karl Strand.Aluna and Hoku, Kampii from the City of Shifting Tides, and their friends, Equian Dash and winged Aviar Calli, are determined to stop a war. The maniacal ex-scientist Karl Strand is planning to conquer the world with his enormous army of tech-enhanced soldiers . . . unless the four friends can get to Strand first. Aluna's plan is dangerous: pose as Upgraders and infiltrate the army. But the enemy isn't what they expected and the strategy begins to crumble. When the friends are torn apart by conflicting allegiances, their slim chance of avoiding war seems to disappear completely. For Aluna and Hoku, what began as a quest to save their own people has become a mission to save the world. But do Aluna and her friends have any hope of defeating Strand if they can't take him on together? less