Only Human is the conclusion to the Themis Files trilogy by Sylvain Neuvel, following Sleeping Giants and Waking Gods. In this installment, trouble with the aliens who built the giant robot Themis leads to trouble on Earth, and three kidnapped humans making their way back find themselves in home they don’t recognize anymore. While it’s not that different in tone from the first two books, I have to admit, the premise of the world stereotypically collapsing into fascism and war grated a little. But even so, I enjoyed the story, and I’d still put this book in the middle of the trilogy in quality.

My rating: 4.5 out of 5.

Big Spoilers Below

Only Human is by far the most complicated of the three books to explain, and I pretty much have to tell half the plot to do it justice, so you have been warned. When last we left the world of the Themis Files, Earth was reeling from the “attack” by the alien robot-builders, now named the Ekt, who killed a hundred million people, but then left after being defeated by an Earth microbe.

That sounds like a remake of The War of the Worlds, but it isn’t. One of two central conflicts of the book is the one sounding the Ekt’s extremist version of Star Trek’s Prime Directive of non-interference. The Ekt’s law of non-interference was not benevolent, but was instead deeply reactionary. It started thousands of years ago, when the Ekt built an interstellar empire and interbred with the residents of other worlds freely (because they apparently could). Then, the conquered peoples rose up in a vaguely-explained revolution that was so devastating that the Ekt vowed never to interfere with other worlds again. They forced all of their descendants of partial Ekt blood to come back to their home world, where even there, they are treated like second-class citizens and subjected to borderline ethnic cleansing because even on the homeworld, the “alien” genes must be bred out of the population.

On Earth, the few Ekt overseers who were left behind continued to interbreed with the human population against their orders until today, 99.9% of the human population has measurable alien DNA. This presents a problem for the Ekt. They at least have enough sense that they don’t want to murder seven billion people, but they also view humanity’s very existence as morally obscene. Last time, they left after Rose Franklin, one of the few pure humans, damaged one of the robots using a bacterium that was discovered by chance to be able to eat the exotic metal hulls, thus “proving” that humans could succeed without alien help. But the Ekt still aren’t sure they should leave it at that. We learned in the last book that literally bombing Earth back to the primordial ooze isn’t out of the question to “cleanse” it of their influence.

In any case, at the end of the last book, Rose and Themis’s pilots, Vincent Couture and his daughter, Eva, were accidentally taken back to the alien homeworld of Esot Ekt. This presents another problem: if, with their tiny amount of Ekt DNA, the humans qualify as Ekt, they have to stay forever. If not, they’re required to be sent back—but the knowledge they gained on Ekt could contaminate Earth further.

Nine years pass, and Vincent finally takes matters into his own hands, hatching a plan to get back to Earth (even though Eva, who was ten when they arrived, views Ekt as her home). Unfortunately, the Earth they return to is very different. The United States has turned basically fascist, and other countries are worse. With the only working robot, untouchable by the world’s militaries, America has embarked on a campaign of world domination. People with anomalously large amounts of alien DNA are blamed for the attack and are rounded up into concentration camps, or worse (despite also being the ones who pilot the robot). And in the middle of all this, Rose, Vincent, Eva, and Themis land in the middle of Russia…

So, as I said, the themes are dark and troubling. Neuvel falls into the old trope of alien encounter stories that humans are violent and barbaric—in almost as many words. He specifically suggests that humans are too “young” and “immature” as a civilization to act responsibly and peacefully. This despite the fact that the Ekt are arguably just as bad in some ways, if not worse.

Ironically, I feel that Only Human had the most conventional ending of the series, with less of the last-minute twists of the first two books (thought that is still there). On reflection, the message was not very good, but I still think the story flowed better than Waking Gods and adequately answered the confusing questions raised in the earlier books. And I enjoyed the story, so at the end of the day, I would still recommend it.