Cambodia is becoming increasingly popular as a holiday destination for backpackers and gap-year students who are interested in the low cost of living that makes for a cheap long-term stay. But although Cambodia has been at peace for seven years, there are still hazards for visitors.
The posters started going up towards the end of last year.
The first one I saw was on the noticeboard of the Foreign Correspondents' Club.
Despite the name, this is not really a haunt for journalists, but actually the most popular bar and restaurant on the Phnom Penh riverfront.
The photocopy was a little too dark, but there was no mistaking the message.
"Missing son - Eddie Gibson" said the text at the top.
Along the bottom, an appeal to call the British Embassy. In the middle, there was Eddie himself, beaming out in high contrast black-and-white.
I tried to imagine what Eddie was like and what might have happened to him.
He looked young, happy, well-groomed. There was not a hair out of place or so much as a hint of stubble.
Perhaps he looked a little naive as well, after all he was only 20.
A range of possibilities came to mind.
A few months later, in another restaurant just up the road from the FCC, Mike Gibson was holding a copy of the same poster in his hands.
Eddie's father was midway through a week-long visit to Cambodia, and he was finding the going rather tough.
"It's like reading a novel," he said. "And you don't know what's going to be on the next page."
As Mike describes it, Eddie's story does indeed sound like something lifted from the kind of thriller you would pick up for holiday reading.
Last October, a few days into his course at Leeds University, Eddie dropped out.
He did not tell his tutors, or even his family. He just took the first flight he could to Thailand.
From there Eddie quickly moved on to Cambodia, coming over the land border at Poipet.
Then on to Phnom Penh, where the story takes on more pulp fiction overtones.
Eddie checked in and out of various hotels and guesthouses in the city centre over the course of just a couple of weeks.
Sometimes he registered in his own name, at others he called himself Micky Gellar.
It turns out that Micky is a friend from Eddie's hometown of Brighton, and knew nothing of his phantom appearances in Phnom Penh hotel registers.
Then there was the girl. Eddie met Ami, a local woman, at the Heart of Darkness bar.
He introduced himself as Micky.
Like many local night spots, the Heart is something of a pick-up joint.
So-called "taxi girls" make themselves available to the Western men who can keep them in relative comfort for the duration of their stay in Cambodia.
Ami and Eddie stayed together in some of the Phnom Penh hotels, but he left several times to return to the border at Poipet, saying he needed to get money.
The last time anyone heard from Eddie was on 24 October.
That was when he sent an e-mail to his mother, Jo, telling her that he would be home on 1 November.
He gave the details of the flight, and the family were at Heathrow to welcome Eddie back. But he never arrived.
Since then, Mike Gibson has probably found out more about his son's activities in Cambodia than he bargained for.
"There should be a health warning on countries like this," he tells me. "If you want to go somewhere and be unaccountable, this is the ideal place, because there are no rules."
People who live here often say that you can buy anything in Cambodia.
It is mostly true, and the prices are usually extremely low by British standards.
That is all to the good when you are talking about beautiful silks, tailor-made clothes or hand-crafted furniture. But there is a dark side as well.
Heroin, marijuana and potent methamphetamines known as yabba or "Nazi speed" are cheap and widely available.
Some of the dealers target the Westerners flaunting their relative wealth at the clubs and bars around Phnom Penh, where a cocktail could cost a local person three days' wages.
And occasionally there is a high price to be paid.
Several British tourists have been found dead in their hotel or hostel rooms already this year. The local drugs were more powerful than they bargained for.
There are also tales about "taxi girls" turning the tables on their clients, and keeping them high on yabba while relieving them of their cash.
Mike does not want to believe that Eddie got mixed up with hard drugs.
And he thinks that his son's relationship with Ami was on more of a romantic, rather than a business, basis.
But he admits there is an atmosphere in parts of Phnom Penh that leads people to consider doing things they would never dream of at home.
It is not like it was a decade ago, when young tourists coming to Cambodia faced the risk of kidnap by the Khmer Rouge.
Now the dangers are more subtle, but the consequences are potentially just as devastating.
Six months on from their last contact, Eddie's parents hope their son has simply chosen to disappear for a while, but they are also bracing themselves for the worst.
From Our Own Correspondent was broadcast on Saturday, 9 April, 2005, at 1130 BST on BBC Radio 4. Please check the for World Service transmission times.