Two years ago, Edgar Tang was driving with his radio tuned to the BBC.
He heard a documentary about a man infected with HIV, the virus that causes Aids.
After a series of radical medical interventions in 2009, the man found himself clear of the virus.
For all practical purposes, he had been cured of the HIV infection, the first person in the history of the disease to have that outcome.
Tang, now 38, was transfixed.
This mysterious and very lucky survivor, an American living in Germany at the time, would be called The Berlin Patient, after the city in which he received the stem-cell treatments that would clear him of the disease.
That fascination would result in the documentary I Hugged The Berlin Patient, which opens tomorrow at the Cathay Cineplex Cineleisure Orchard.
As Tang says in the film he co-directed, the patient, whose real name is Timothy Ray Brown, was "an underdog you want to cheer, an outsider.
Suddenly he is thrust into a world where he is put on a pedestal, to become the chosen one.
He never guessed he would be this special person, the first person to have been cured of HIV".
Speaking to Life!, he says that the idea for making a documentary about his search for Brown came about by chance.
"I had a month to spare from work. I didn't think about doing a documentary. I thought I would go to Berlin and get inspired by his life to write a fictional feature about his experience."
He called a friend and former classmate Dzul Sungit, 38, to see if he wanted to go with him. Dzul decided to capture on video Tang's trip to Germany to see if anything interesting would come of it.
Now a senior producer for on-air branding and promotions at HBO Asia, Tang fought Hodgkin's Lymphoma, a form of cancer, in 2007, and has been clear thus far.
Dzul was intrigued by Tang's interest in looking for Brown and placed Tang and his search for Brown as the driving force of the film. The suspense of the chase - will Tang find Brown? - drives the story.
On the film, Tang also reflects on his own battle with cancer, and how Brown's journey bears some similarities with his own. The 73-minute documentary is Tang's first full-length work.
He had made short films and was recently creative producer for the Ken Kwek film Sex.Violence.FamilyValues.
A student of mass communications at Ngee Ann Polytechnic, he received a Media Development Authority scholarship to study film in New York in 2009.
The film shows how, in Berlin, Tang's effort in finding Brown hits a wall, though they managed to interview Dr Gero Hutter, the haematologist whose team took stem cells from a donor who was naturally immune to HIV and transplanted them into Brown.
Brown subsequently developed a resistance to the disease and stopped taking medication for it.
After a fruitless six days, a frustrated Tang put on a sandwich board the line: "Do you know who The Berlin Patient is?" in English and German.
For three hours, he walked the busy Schoneberg district of the city, where Brown is thought to have lived for a while, asking passers-by if they knew where he was. "I guess I am quite theatrical, generally," he says.
His random interviews showed that few had heard of either Brown or the fact that medical history had been made in their own city.
"It got the attention of people on that street, and I am glad we got it on film," he says of the stunt.