Thirteen-year-old Aluna has lived her entire life under the ocean, just like all of the Coral Kampii in the City of Shifting Tides. But after remaining hidden from the Above World for centuries, her colony is in trouble, its survival in doubt : the tech that allows the Kampii to breathe underwater is beginning to fail, and many Kampii have already died. Yet the colony’s elders, including Aluna’s father, are unwilling to venture to the dry and dangerous Above World to search for answers. So it’s up to Aluna and her friend Hoku to face the terrors of land to find a solution.
After an incident shatters their family, 11-year old Samantha and her older sister Caitlin are sent to live in rural Oregon with an aunt they've never met. Sam wants nothing more than to go back to the way things were…before she spoke up about their father's anger. When Aunt Vicky gives Sam a mysterious card game called "A Game of Fox & Squirrels", Sam falls in love with the animal characters, especially the charming trickster fox, Ashander. One day, Ashander shows up in her room and offers Sam an adventure and a promise: find the Golden Acorn, and Sam can have anything she desires.
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. Aluna’s plan is dangerous: pose as Upgraders and infiltrate the army.
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 and forming an alliance. Unfortunately, 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.