The strangeness and physicality with which Arian depicts life in Evin Prison makes for a convincing, unnerving read.

THEN THE FISH SWALLOWED HIM
By Amir Ahmadi Arian
277 pp. HarperVia/HarperCollins Publishers. $25.99.

The New York Times: “Crime is something relative,” Mohamedou Ould Slahi writes in “Guantánamo Diary,” his memoir of imprisonment at Guantánamo Bay, where he was held for 14 years. “It’s something the government defines and redefines whenever it pleases.”

Such whispered warnings drive the tension in “Then the Fish Swallowed Him,” a story of entrapment and torture in Tehran’s notorious Evin Prison, and the first novel written in English by Amir Ahmadi Arian, an Iranian-born former journalist who now lives in New York. In 2005, a lonely Tehrani bus driver named Yunus (after the prophet Jonah, who is swallowed by a big fish) attends a union strike. Shaken by a changing Tehran and worsening conditions for the working class, he has read Foucault, Al-e Ahmad, Marx, Engels and other political writers. After the bus drivers’ strike turns violent, Yunus becomes a scapegoat for the whole operation. In prison, he isn’t a simple man who stumbled into a movement; he is its doomed architect.

The strangeness and physicality with which Arian depicts Yunus’s prison life makes for a convincing, unnerving read. He invites us to notice the taste of prison tea, the heightening and dulling of sensation after torture, the bliss of a power outage that offers prisoners a few hours of night. When Yunus begins to unravel, befriending a fly, reliving the death of his parents and walking around his cell as if it’s the city, he is poignant and tragic.

Arian offers straightforward and astute observations about Iran’s attitude toward Western powers and about the social history of modern Tehran. His insights into the lives of the city’s poor at a time of mounting inequality, and on the effects of sanctions and Western media on average Iranians, are gripping. I was struck by his description of a car ride during which prison guards discuss smuggling Western medicine to a sick child and the appeal of becoming refugees themselves.

But Arian’s talents are primarily journalistic; too frequently his novel reads like a political lecture. If his eye is keen, his ear — for poetic English, at least — is not, and he often produces off-key prose garbled by mixed metaphors: “The cacophony I had lived in my whole life came to me in strands of sound tangled like yarn. … The noises snaked in from all sides, scarring the air, snarling into knots in my head, forming balls of hum and whir.” He sometimes transitions awkwardly between the literal and figurative, not trusting the reader’s imagination to complete images. Special guards are “like mutated beetles escaped from a lab.” The prison is “a coffin made especially for the buried-alive.” Tehran in the 1990s is bloated “like a balloon attached to an air pump that never turned off.” Aren’t “beetles,” “coffin” and “balloon” enough?

Arian’s publisher compares this novel to “1984” — which is ironic, since Orwell was obsessed with linguistic precision and the decline of English. And yet, as Big Brother, Yunus’s prison interrogator is perfectly chilling, especially in his moments of calculated grace. We know what he wants: for Yunus to believe him, to love him, to miss him. “The system is not afraid of you,” he says.

Before Yunus lands in Evin, an activist warns a group of strikers, “Your interrogators are trained to make you contradict yourself.” Then those same guards get into a car and discuss fleeing abroad, forgetting that every country has its interrogators, its gatekeepers, its tricks. “Thousands of people have done it,” one guard says about being smuggled to Australia by plane and boat. “When you get there, you’re fine.”

This novel is an uncomfortable deep dive into the belly of a beast that swims in every sea. In prisons like Evin or Guantánamo, ordinary people are broken, then blamed. If one day they arrive in safer, freer countries, they might find that their torturers have followed them, the same accusations on their lips. After a beating, a prison worker says of Yunus’s injuries, “Look what you have done to yourself.”

Dina Nayeri is the author of “The Ungrateful Refugee,” a work of nonfiction, and two novels.