The Humans by English author Matt Haig is a novel that combines the genres of science fiction, psychological fiction, bildungsroman, and fictional diary. Published by Simon & Schuster in 2013, it is Haig’s fifth novel. The Humans is structured as a scientific analysis of life on Earth, but it is also about the personal experiences of an extraterrestrial who struggles to reconcile the paradox of human life. The plot is driven by the urgency of the alien’s mission. Within his story, Haig uses his first-person narrator to explore themes on what it means to be human, how to pursue happiness, and the power of embracing love.

Content Warning: The source material and this guide include discussions of suicide, including some graphic imagery.

Plot Summary

The Humans begins as a scientific report on the observations of one alien on planet Earth. The narrator acknowledges his home planet’s trepidation that human beings are dangerous and impulsive, but he encourages his reader to have an open mind as he tells his story. The narrator is sent to Earth to take on the form of the recently deceased Andrew Martin, a prolific professor of mathematics at Cambridge University. Professor Martin solved the Riemann hypothesis, thus confirming the possibilities of extraterrestrial life and the potential for human progress.

When the narrator arrives as Andrew, he is stark naked and knows nothing about Earth except for the prejudices against human avarice he learned on his home planet. His mission on Earth is to erase all traces of this Riemann hypothesis. He stumbles through the city searching for Andrew Martin’s home and is apprehended by authorities on his university campus for public nudity. Andrew is institutionalized for mental health issues and is disgusted by the look of the human beings around him. He finds the food he is given repulsive and is disgusted by the humans and their irrational, unstructured, technologically unadvanced world. When he is released from the hospital, he wipes away the evidence of the Riemann hypothesis on Andrew Martin’s computer and kills his mentor, with whom Andrew Martin had discussed his solution. His next step is to eliminate Andrew’s son, Gulliver.

As Andrew bides his time to find the right moment to eliminate Gulliver and Andrew’s wife, Isobel, he starts to discover comfort on Earth. He is mesmerized by music, impressed by poetry, inspired by a new friendship with the family dog, Newton, and delighted at the taste of peanut butter. He starts to enjoy his life as a human. As he becomes more comfortable on Earth, he develops irrational feelings for Andrew Martin’s family and friends. His home planet warns him to stay focused and not to be seduced by the dangerous influence of the humans. His mission begins to weigh heavily on his heart, and his human emotions scare but excite him. Before long, he finds himself in love with Isobel. Isobel and Gulliver are alarmed at the change in their father and husband. A man who had been inattentive and obsessed with his work and reputation for decades is suddenly showering them with affection and advice.

Andrew ultimately decides that he cannot go through with the rest of his mission. He tries to convince his hosts that Isobel and Gulliver don’t know enough to pose a risk, but they insist that he complete the mission. Andrew decides to become fully human, leaving his incredible extraterrestrial powers behind. On Earth, he has discovered the warmth of a family and the power of love, and he doesn’t want to give that up.

When Andrew becomes a human being, the aches and pains of human life complicate his experience on Earth. As he learns to adapt to social codes and norms, he worries that his home planet has sent another alien to eliminate Gulliver and Isobel. Despite this danger, things go well for Andrew for a while. He repairs his relationship with his depressed son, and he revives his relationship with his wife. However, when Andrew has sex with a student (not realizing what infidelity and monogamy are), he ruins the new life he has created with the Martin family. After his friend Ari is killed, Andrew knows for sure that another alien has arrived to finish his job. When the new alien, Johnathan, tries to kill Gulliver, Andrew intervenes and kills one of his own species. Isobel and Gulliver watch in confusion and horror. Knowing that it is impossible for human beings to accept his story, he leaves the family and creates a solitary life for himself in California. While he self-medicates with alcohol, travel, and nature, Andrew continues to pine for the love he shared with Isobel. He returns to England to give a lecture and resolves to take the risk of pursuing happiness and seek out Isobel’s forgiveness and acceptance.