Washington — The phone call came from the nursery school teacher who wanted Xua Qu to know that her three-year-old son, Shaofon, was telling strange stories to other preschoolers about his father.

"He started saying to his daycare friends — his three- and two-and-a-half-year-olds — that his dad was taken by bad guys, and is being kept in a dungeon," she said.

That storybook description was not terribly far from the truth. For the past three years, Princeton University scholar Xiyue Wang has been languishing in an Iranian prison on what the U.S. government calls trumped-up charges of espionage. The ancient literature scholar was arrested during a 2016 research trip that he was conducting as part of his doctoral work.

"He is in a very cramped underground cell with no natural light, living together with over 25 cell mates," Qu described to CBS News in her first network tv interview.

Xiyue Wang, his wife Xua Qu and their three-year-old son, Shaofon CBS News

"He is in the middle of a three-tiered bunk bed. He developed a series of medical conditions — stomach rashes, arthritis, especially arthritis in both of his knees," she recounted.

Wang is permitted to make around three phone calls a week to his wife and son. Shaofan is now six years old and relies on photos and home videos to remember what his father looks like. Qu shared a recent picture Shoafon drew of the entire family making snow angels in a snowstorm that hit Princeton the day before Xiyue departed for Iran.

It is nearly impossible to explain to a child that his father is at the center of one of the most tense geopolitical standoffs, with the risk of a military clash between the U.S. and Iran remaining high. Trump administration officials told CBS News that there are no direct talks underway between the two countries, and they did not consider a recent offer by Iran's foreign minister Javad Zarif to conduct a prisoner swap a serious one.

An internal jockeying for power within Iran's leadership as the country undergoes an economic crisis exacerbated by U.S. sanctions has only added to the complications. Even before President Trump exited the landmark nuclear accord between the U.S. and other world powers, Zarif and other architects of the deal have not been able to deliver the financial relief from sanctions they promised it would deliver. That has further put those who favor engagement at odds with the country's hardliners.

Xiyue Wang and Shaofon

Washington Post Journalist Jason Rezaian lived and worked in Iran before being imprisoned there for a year and a half on charges of espionage.

"The Iranian regime is very much entrenched, and there are domestic, political considerations that we have to take into account inside Iran," he told CBS News. "So as much as I think the foreign minister Javad Zarif and others in the Iranian regime know that they would have to negotiate with the United States at some point, I think rushing to negotiate would be political suicide for them."

At the center of this standoff, there is a six-year-old boy who has now lived half of his short life without his father by his side, unable to comprehend the unjustness of it all.

"We recently moved to a new apartment, in the first night he asked me, 'Since we have moved, will my dad still find us?' Because he's worried, and he's processing these hard questions in his mind," Qu said.

Yet, the Trump administration has had success in bringing other Americans home from other rogue countries. Mr. Trump often brags that he has not replicated the 2016 Obama-era deal to swap prisoners with Iran. It was that agreement, which coincided with the implementation of the landmark nuclear accord and the release of $1.5 billion in frozen Iranian funds, that allowed President Obama to win the release of four prisoners, including Rezaian.

Jason Rezaian, one of the U.S. citizens recently released from detention in Iran, meets the media together with his wife Yeganeh Salehi outside the Emergency Room of the Landstuhl Regional Medical Center (LRMC) in the southwestern town of Landstuhl, Germany, January 20, 2016.Rezaian was one of four American prisoners released by Iran ahead of the lifting of international sanctions on Iran January 16, 2016 -- part of a deal between major powers and Iran to curb Tehran's nuclear program. Kai Pfaffenbach/Reuters

"I think the reality is that President Trump has had success bringing hostages home from other countries besides Iran," Rezaian said. "And while the stated policy of this administration and every administration going back several decades is one of no concessions, when you read the fine print, there's always a concession. There was always something given to the other side to win the release of American citizens."

Rezaian added that he sees the opportunity for a prisoner release as a way to cooling the escalating tensions with Iran.

Since the 1979 hostage crisis, virtually every president has had to decide whether to craft a controversial deal to release American prisoners. Presidents Carter, Reagan and Obama all did so.

Despite that he has made bringing Americans home a signature issue for his administration, Mr. Trump has not had any success with Iran.

While State Department officials have written letters to Foreign Minister Javad Zarif in recent months urging him to advocate in Iran for the prisoners to be released, they've had no success. Behind the scenes, officials have asked Switzerland, Oman and even China to intervene on the Americans' behalf. So far, none of their entreaties have worked.

Now, Qu said she is pleading publicly in order to get Mr. Trump to directly intervene, and decided to speak to journalists now to raise the profile of her husband's case. She fears he has been forgotten.

"I don't want to fail Xiyue, and I don't want to fail my son," she said. "And it's really scary."