Children tell themselves stories to bring comfort, to give names to what is difficult in an effort to control a narrative that is out of their hands.

As a little girl, growing up in Huntsville, Alabama, Gifty begins to keep a diary — extracts of which pepper the early pages of this moving novel — in which she calls her mother the Black Mamba after watching a film in school that shows “a seven foot-long snake that looked like a slender woman in a skin-tight leather dress, slithering across the Sahara in pursuit of a bush squirrel”. Gifty’s parents met in Ghana and emigrated to the US thanks to the green card lottery; the father she barely knows is named the Chin Chin Man, after his fondness for the deep-fried snack of that name. While her beloved older brother, Nana, is known as Buzz; Gifty can’t recall why she called him that — although as the reader encounters him, the name suits his energy and vigour — until disaster strikes.

Yaa Gyasi made her name with Homegoing, published in 2016. The novel was chosen for the National Book Foundation’s 5 Under 35 award and won the National Book Critics Circle’s John Leonard Award for best first book. Homegoing traced the harrowing cost of enslavement down generations of African-American lives, using the fracturing of a family to show how history and fate entwine. In Transcendent Kingdom, too, a family is fractured, though Gifty’s family comes from the African continent to America of their own volition. But in so doing, they discover what it means to be black in the US in the 21st century; their new lives are ones of opportunity, but those opportunities don’t come without cost.

The novel begins as a flashback: Gifty is 11, and has been sent “home” to Ghana to be looked after by her aunt while her mother recovers from what is at first an unspecified illness. In the novel’s contemporary present, Gifty’s mother arrives in Stanford California, where her 28-year-old daughter is working in a lab: Gifty is a high achiever, a sixth-year PhD candidate in neuroscience at Stanford’s School of Medicine. She studies reward-seeking behaviour in mice, whether they will tolerate electric shocks in exchange for treats. It soon becomes clear that there is a direct link between Gifty’s past and her present: when she was 15, a high-school biology teacher urged her towards science just as her mother discovered a stash of OxyContin, an addictive synthetic opioid, in Nana’s room.

Nana’s addiction, and his death as a result of an overdose, is the ravaged heart of this novel; but this family also has to contend with being African in America, rather than African-American. Gifty’s mother, a home health aide, “almost never admitted to racism”, though one of her employers always refers to her in offensive language. Gifty’s tall, charming, imposing father discovers that he is perceived very differently in the US than he was in his homeland: Gifty’s mother observes “how America changed around big black men. She saw him try to shrink to size, his long, proud back hunched as he walked with my mother through the Walmart, where he was accused of stealing three times in four months.”

Gifty survives by becoming the star student, the exception: “I wanted to flay any weakness of my body like fascia from muscle.” But she must come to terms with her family’s past when her mother’s illness — depression — strikes again. In taking her mother into her apartment in California, and caring for her, Gifty is forced to balance her cold and clinical lab work with the aftershocks of her history.

Gyasi’s first-person narrative is confiding and atmospheric as she contrasts Gifty’s ordered life in the lab, her studies of addiction, with the disorder of her early years: “What I can say for certain is that there is no case study in the world that could capture the whole animal of my brother, that could show how smart and kind and generous he was, how much he wanted to get better, how much he wanted to live.”

If this novel has a weakness, it is that there is perhaps a little too much of the case study about it, a line too neatly drawn between Nana’s addiction and the opioid epidemic that continues to beset the US. In 2017, the Department of Health and Human Services declared it a public health emergency: opioids were involved in 46,802 overdose deaths in 2018, according to the Centers for Disease Control and Prevention; two out of three opioid-involved overdose deaths involve synthetic opioids such as OxyContin.

About a third of the way through the novel, Gifty tells one of her lab mates about Nana’s death and how it relates to her own work. “‘This would make such a good TED talk,” the friend says. That’s just the trouble: Gyasi’s novel can, at times, feel as if it is too directly addressing these difficult issues rather than fully embodying them in fiction. But Gyasi’s warmth and energy makes the reader forgive her earnestness: this is an absorbing, moving book.

Transcendent Kingdom, by Yaa Gyasi, Viking, RRP £14.99, 256 pages

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