Horn Book (Fri Aug 01 00:00:00 CDT 2014)

Aluna and her friends disguise themselves as cyborg Upgraders in order to destroy Karl Strand once and for all. To win the war, however, they will need to strengthen existing friendships and forge new alliances among their world's diverse beings. This concluding installment, which features believable world-building, fast-paced action, and engaging characters, wraps up the series nicely.

Kirkus Reviews

This last volume of the Above World trilogy opens where Mirage (2013) ended, with Aluna, Hoku, Dash and Calli determined to save their genetically modified races from megalomaniac Karl Strand and his technically enhanced Upgrader army. Masquerading as Upgraders with Aluna and Calli pretending to be their prisoners, Hoku, an ocean-dwelling Kampii, and Dash, a desert-dwelling Equian, join an unsuspecting Upgrader kludge to find Strand. When they are captured by Silvae—flying squirrel–like tree dwellers—and separated from the kludge, Aluna, Hoku, Dash and Calli split to fight Strand on different fronts. Dash rejoins the kludge, hoping to rescue his Equian relatives captured by Strand. Calli returns to the Aviars, who are under attack from Strand's army. Aluna and Hoku join their Kampii families in the ocean, still trying to find Strand and devise new breathing devices. The four friends use individual strengths forged through their time together to help their respective races while staying committed to the common goal of defeating Strand. Aluna remains a compelling warrior, and Hoku, Dash and Calli come into their own as the fast-paced action ricochets back and forth, culminating in a colossal confrontation with Strand. A fitting finale for a gripping futurist series whose four multifaceted heroes offer a strong anti-war, pro-diversity message. (Science fiction. 10-16)

School Library Journal (Tue Apr 01 00:00:00 CDT 2014)

Gr 6 Up-As the diabolical Karl Strand plans to conquer the world with an army of high-tech soldiers, Aluna and her friends decide to infiltrate the enemy by posing as Upgraders.

Voice of Youth Advocates

Their quest to destroy the megalomaniac Karl Strand is postponed as Aluna and her friends separate to pursue personal missions.á Their individual battles ultimately lead back to their initial purpose, however, and the friends reunite to face the bioengineered beast Strand has become. The Above World series is rare in that it actually improves with each sequel.á Horizon is a much better book than the debut novel would lead one to expect.á Igniting most of the adventures are the various conflicts the friends face separately, even as their struggles are woven together throughout the novel.á This fact might actually confuse some readers since the point of view changes after every few chapters.áAlthough the novel incorporates a lot of violence, the storytelling seems to assume a younger, or perhaps merely a less sophisticated, audience.á The characters are pointedly described as being more mature than they were in the beginning, but their personalities and attitudes seem much like they did in the first novel.á The lack of nuance in the villains is disappointing.á Just as the good guys are interminably good, the bad guys are relentlessly bad.á In the end, as Hoku fights to create a connection to Strand, the reader may detect a glimmer of hope that Strand could turn from the dark side, but that spark is quickly extinguished and he remains as evil as ever.á Nevertheless, it is an entertaining novel that will provide a satisfying conclusion to the series for fans.Cheryl Clark.