BENGHAZI // At first, it did not sink in. Front line? Front of what line? A concert or movie queue? A beach volleyball game? No, the caller said, your son is at the front line of the Libyan civil war with rebel fighters trying to oust a notorious despot.
Peter Jeon was stunned. "A friend said Chris was on the news, so we went on the internet," said Mr Jeon, an orthodontist in Orange County, California. "Obviously, we were shaken."
For the first 10 weeks of the summer, according to a friend, Mr Jeon's 21-year-old son Chris had worked as an intern at BlackRock, the world's largest asset management firm.
Two days after he finished, he boarded a plane bound for the Middle East, saying he was going to Egypt for some time off before entering his senior year as a maths major at the University of California, Los Angeles (UCLA).
But instead of visiting the pyramids and strolling along the Nile river, Chris decided to venture west to neighbouring Libya, where he took up with a group of young rebel fighters and accompanied them along the coastal road towards Sirte, the hometown of Colonel Muammar Qaddafi and one of the last strongholds of his loyalists.
It was near the small village of An Nawfaliyah late last month that The National met Chris, who was wearing camouflage trousers and a vintage basketball jersey bearing the script "Los Angeles", and carrying an AK47.
The sheer incongruity of this Californian roadtripper turning up in a civil war in the North African desert made Chris a front-line celebrity.
The insurgents dubbed him "Ahmed El Maghrabi Saidi Barga" - a nickname cobbled together from the names of villages and tribes that dot that part of northern Libya.
While the story of what Chris was doing on his summer holidays spread across the internet and made him a cyber sensation, he had no way of knowing that his family had found out about his secret trip. He had no access to a phone or a computer in the towns along Libya's Mediterranean coast.
Chris asked reporters from The National and the Christian Science Monitor not to tell his parents he was in Libya. "They don't know I'm here," he said, after explaining that he had thought it would be "cool" to join the rebels for his summer holiday.
In the week since first hearing about his son's whereabouts, Mr Jeon canvassed the internet, contacted journalists in Libya and established his first Facebook and Twitter accounts to try to keep up to date with his son.
Finally, the call he was waiting for came on September 5. Hoda Abdel Hamid, a correspondent in Libya for Al Jazeera, handed her satellite phone to Chris and he called his parents in Orange County, 11,000 kilometres away.
Chris told his father in their short, patchy conversation that he was well and heading home soon.
Since their phone conversation, the "level of anxiety has gone down", Mr Jeon said dryly, adding that his son "appeared not to know about all the attention he has received".
"He is safe, in good spirits and well treated by locals," Mr Jeon said. "We will be happy to see him home soon."
When that might be is unclear. Chris purchased a one-way ticket to Cairo and was planning to buy the return ticket with his credit card when he decided to return.
Doctors in Ras Lanuf said on September 2 that Chris had stayed the previous night at a field hospital on a couch and was in good health. His whereabouts yesterday were not known.
Mr Jeon agreed to speak publicly for the first time about Chris's road trip because he was keen, he said, to clear up any misconceptions about his son's motivations.
Chris was not a immature war junkie but a passionate explorer who pushed himself to the limit, he said - a young man with a deep curiosity about the world around him.
"He went to see what is taking place in the region and how it changes people's lives," said Mr Jeon. "His role is to show his support and the locals appreciate him."
This is not the first time that Chris has taken a trip that "kept me up at night", Mr Jeon said.
During Christmas break of his freshman year at UCLA, he flew to Cambodia to spend time at an orphanage in Siem Reap and the surrounding countryside, which is still littered with landmines left over from the Vietnam War and the Khmer Rouge's genocidal rule in the mid-1970s.
The following summer he travelled alone to the Amazon region in South America and lived with local families in Ecuador, Peru and Costa Rica, contending with rare tropical diseases, large exotic insects and a yawning cultural divide.
"To him, these are cool vacations and the common thing in all of these is his desire to experience and understand what they go through by staying with them," Mr Jeon said. "They were adventurous."
Chris's presence on a couch at a rebel field hospital earlier this month was fitting.
Before travelling to Libya from Egypt, he contacted Sameeh Lahiwel, 24, a student at the University of Benghazi, through the website CouchSurfing.org and asked for a place to stay.
"I am planning to visit Libya in the coming day to make a documentary on the medical facilities there and how the community is getting health care," he wrote on August 17.
"I was wondering if I could stay with you or people you know for a couple of days because I don't have any contacts in Libya and would be grateful of any assistance.
"I hope we will meet soon and that you will show me your country's culture and lifestyle. "I am from Los Angeles and would welcome you to my home any time."
Chris never did stay with Mr Lahiwel, who voiced surprise at what has happened to the American. "I had no idea he was going to be so famous," Mr Lahiwel said.