Kevin Garratt and his wife Julia in the backyard of a home they’re staying at after recently returning to Canada. FRED LUM/THE GLOBE AND MAIL

The plain-clothed men who grabbed Julia and Kevin Garratt from a restaurant in northeastern China said they were police. But that was little consolation. “You are a spy!” they bellowed at Ms. Garratt, before dragging her into a black car and driving her out of the city. Her husband was taken away separately.

“For the first time in my life, I felt this could be my last night alive,” she writes in Two Tears on the Window, a new self-published book that recounts in vivid detail what happened during more than two years the couple spent caught up in Canada’s relations with an authoritarian state that is the world’s second-largest economy.

It’s “really a survival story,” Ms. Garratt said in an interview. It’s about “how you cope with suffering and how you maintain your relationship as a couple when you’re isolated.” They also intend it to be a testament of faith amid dark circumstances: “When your hope is placed in God, you can get through things,” Mr. Garratt said.

The account contains startling new details about the couple’s treatment in detention, which lasted six months for Ms. Garratt and 775 days for Mr. Garratt after the couple were accused of collecting and stealing intelligence materials.

Interrogators seeking confessions repeatedly threatened execution. Mr. Garratt was regularly questioned while locked in a tiger chair, a painful restraining device. The devout Christian’s health deteriorated to the point that he feared imminent death. “My next meal will either be with Julia or Jesus,” he told a consular officer, nearly two years after he and his wife were seized by Chinese authorities.

It’s widely believed they were apprehended in August, 2014, as reprisal against Canada for the arrest, weeks earlier, of Chinese citizen Su Bin in British Columbia. Mr. Su was sentenced in the United States to nearly four years in prison for his role in organizing the hacking of technical data on military aircraft.

The Garratts do not allege mistreatment beyond what is common in China; in fact, they were provided some favours, such as Christmas meals (for which they were later billed). But their account details the human cost of an international dispute with China.

Two Canadian prime ministers raised the Garratts’ detention with Chinese leadership. Even so, the couple have questions about Ottawa’s efforts.

More than 600 days after Mr. Garratt was taken away, Ms. Garratt and James Zimmerman, an American lawyer, met with Canadian diplomats in Beijing. “So, what’s the plan now?” Mr. Zimmerman asked. “There isn’t one,” a Canadian consular-affairs co-ordinator responded. “It’s a waiting game. We keep raising the case at every opportunity and hope the trial will be soon.”

“Canada didn’t know what to do,” Ms. Garratt writes.

They first came to China in 1984 as newlyweds to teach at the National University of Defense Technology, selected by officials as the first foreigners since the Communist Revolution to deliver English lessons at the military institution.

They joked about being chosen “because we were young and least likely to be spies,” Mr. Garratt writes.

From that time on, their lives were dominated by China, where they delivered English lessons, worked with orphanages, consulted and, in 2008, opened a coffee shop. Although some of their work was supported by foreign churches, they call themselves Christian non-profit workers rather than missionaries.

“I introduce God by being myself,” Ms. Garratt told her Chinese interrogators in the first few months of her detention, when she and Mr. Garratt were held separately in brightly lit rooms with guards keeping constant vigil.

Daily interrogation sessions lasted for hours, as the Ministry of State Security found suspicion in even the smallest interactions discovered on seized computers.

“They were desperate for proof.”

They ultimately found it in Mr. Garratt’s interactions with diplomats, some of whom had come to the couple’s coffee shop in Dandong, a city on the North Korean border that offers a unique outlook on that isolated regime. Mr. Garratt had also been asked to meet the Canadian Security Intelligence Service (CSIS) in Canada to discuss North Korea, where the couple did charity work. Chinese interrogators told Ms. Garratt that because a CSIS agent had signed an e-mail to Mr. Garratt with only a first name, that meant “they work together.”

The Chinese military also deemed 23 photos he had taken “highly sensitive or sensitive.” One was of the Friendship Bridge between China and North Korea, a tourist attraction.

“How can bridge photos be classified as sensitive?” Mr. Garratt asked. “It’s the angles of the photos,” he was told.

In between interrogation sessions stood spirit-sapping monotony. To pass the time, Ms. Garratt tapped Chopin waltzes on an air piano. She sketched the outlines of a PhD thesis. She snipped tiny cards out of a sheet of paper and played Solitaire. She befriended some guards and observed others, including one she dubbed Vivian, who “wanted a boyfriend and beat her thighs with fisted hands to get rid of excess thigh fat.”

During separate 15-minute daily outdoor walks, the couple left each other messages in the snow, creating snow sculptures and writing Bible verses.

Ms. Garratt had visions of a physical presence of God, of being transported to a fragrant heavenly garden and of a giant angel pouring a golden liquid of prayers over the building where she was detained.

Ms. Garratt was released on bail in early 2015 and eventually allowed to return to Canada. But pressure extended there, too. Canadian authorities told the family that numerous people boarded a flight to monitor her. In Canada, unknown cars followed her.

That stress compounded frustration over her husband’s continuing detention, particularly as his health deteriorated. Mr. Garratt was diagnosed with a litany of ailments: appendicitis, chronic dizziness, hernias, an irregular heart rate. He suffered numbness in his limbs, headaches and debilitating back pain.

Canadian officials said they made many attempts to have him released on medical grounds. But “our numerous requests for his release had convinced them that he was spying for us,” said Guy Saint-Jacques, then the Canadian ambassador to China.

“Our strategy was to raise the issue at every opportunity, including ministerial visits and to say that this case had to be resolved if bilateral relations were to develop to their full potential,” Mr. Saint-Jacques said. Prime Minister Justin Trudeau forcefully discussed the matter with Chinese leadership in 2016 and secured a promise to release Mr. Garratt within weeks, the former ambassador said.

“Canadian representatives were extremely engaged on this case,” said Guillaume Bérubé, a spokesperson for Global Affairs Canada. “We remain deeply impressed by the grace and resilience the Garratt family, especially Kevin and Julia, demonstrated prior to being released.”

Mr. Garratt’s health has largely recovered since being set free and the couple say they would still like to return to China. What happened “was a political thing,” Ms. Garratt said.

In recounting their story, the couple hope to wring good from their experience. “People come to us and say, ‘Now, my problems seem so small,'” Mr. Garratt said.

The Globe and Mail, November 28, 2018