Nurimaro Park met with attorneys to help him with his DACA case in Falls Church, Va., on Nov. 17. (Michael Robinson Chavez/The Washington Post)

At 26, Nurimaro Park was living paycheck to paycheck, helping support his undocumented parents on a tutor's salary. So when his work permit expired in May, he waited to renew it because the rules allowed for that. He needed time to save up the $495 fee.

Now, he and thousands of others who let their Deferred Action for Childhood Arrivals permits expire are without legal status in the United States. He and another young immigrant in Northern Virginia are suing the Trump administration in federal court in Alexandria, saying their due process rights have been violated.

"You can't change the rules on someone without giving them a heads-up first," said Simon ­Sandoval-Moshenberg, an attorney for the Legal Aid Justice Center representing the two.

Until September, DACA recipients, known as "dreamers," could file a renewal of their two-year permits up to a year after expiration, a policy laid out on the U.S. Citizenship and Immigration Services website.

"Money is a huge issue; $495 is hard to save up," said Park, who lives with his parents in Fairfax County. "You have a year of grace period . . . and I was taking advantage of that."

Nurimaro Park meets with his attorney, Simon Sandoval-Moshenberg, right. (Michael Robinson Chavez/The Washington Post)

Then, on Sept. 5, Attorney General Jeff Sessions announced that the program would end in six months. Although immigrants whose permits are set to expire before March 5 were given the chance to renew them one last time, anyone whose permit had already expired could not.

The DACA program, created by President Barack Obama in 2012, allowed hundreds of thousands of immigrants brought to the United States as children to work legally and attend college.

Although several lawsuits have been filed challenging the termination of the program, this is the first specifically focused on the issue of expired permits. According to the Department of Homeland Security, 50,000 immigrants whose DACA permits expired by Sept. 4 did not renew before that date. The new suit asks a judge to allow those recipients who could have renewed under the old system to have that chance now.

It was from a Korean advocacy group, the National Korean American Service & Education Consortium (NAKASEC), that Park learned he was once again "just illegal."

Park's parents brought him to Northern Virginia from Korea when he was 9 years old. They tried to get legal status but never did, after falling prey to a green-card scam that ensnared more than 100 Korean immigrants in the area in the late 1990s.

He learned of his illegal status in middle school. But the full import of his situation didn't sink in until late high school, when he realized he would not be able to drive a car or afford college.

Park had been the model immigrant child, wanting to live up to the opportunity his parents had given him. Senior year, he said, "I was hopeless." He stopped trying in school and withdrew from his friends.

Park managed to make some money tutoring and working at an auto shop, paid illegally. He applied to Northern Virginia Community College and got an associate degree in computer science, paying an international student's tuition. (Virginia began allowing DACA recipients to pay in-state tuition at state schools in 2014.)

When Obama announced the DACA program, Park hesitated about applying, not wanting to put his parents at risk. But they wanted him to. "It was the right thing to do," he said.

He got legitimate jobs at two tutoring companies and began saving in hopes of going to the University of Virginia for a bachelor's degree.

Unless this lawsuit succeeds or until the administration changes its policy, he could be deported at any moment.

The realization brought Park back to the despair he felt in high school. But now, he said, he's "a bit more mature." Instead of giving up, he became politically active. For years, he said, he was too busy and too scared of deportation. He has begun working with ­NAKASEC to advocate for immigration reform and is planning to move to Los Angeles to take a bigger role in the organization, despite his fear of taking a public profile as an undocumented immigrant.

"It's like a wake-up call," he said. "I'm worried, but I feel like it's a risk I have to take."