He thought it would be a simple day trek.
So Mr Sanjay Radakrishna, 26, decided to scale the highest peak in Cambodia on his own, taking only a 1.5 litre bottle of water, 20 pieces of biscuits - and a graduation gown.
He wanted to take a selfie of himself wearing the gown on the summit, which he managed to do after a five-hour trek up Phnom Aural. It stands 1,813m above sea level.
But the descent took a turn for the unexpected that caused the National Institute of Education undergraduate to end up lost for six days.
As Mr Sanjay was heading down in the afternoon, it started to rain and he decided to jog down the narrow trail. But he tripped and fell down a slope about 10m from the trail.
When he tried to get back to the trail, he realised that he had lost his bearings. And so began his adventure in the wild.
The Singaporean had arrived on June 26 in the Cambodian capital of Phnom Penh, where he met a friend.
He had been planning the trip since the beginning of the year with the aim of climbing the country's highest peak.
On June 28, he was pillioned on a motorcycle to Srae Kan 3, a village near the foot of the mountain.
But he aborted his plan to climb Phnom Aural the next day as it was raining.
At 7am on June 30, he set off up the mountain after notifying the people at his homestay, and his girlfriend via text message.
Clad in a red shirt, shorts and sports shoes, Mr Sanjay had a watch with compass and altitude functions, a mobile phone, torchlight, camera, mini-tripod, and spare camera batteries.
Taking up most of the space in his backpack was a graduation gown he had purchased in advance.
"I wanted to take photos in my graduation gown at the summit," he told The New Paper yesterday after he returned to Singapore the day before.
"It was a normal climb and I reached the summit after five hours," said Mr Sanjay, who said he has scaled 39 mountains in such countries as Malaysia, Nepal and Croatia, since he was 15.
By then, he had run down his phone battery from using its GPS function.
Then it started raining, so he decided to jog his way down the mountain trail.
He said: "The path was slippery, and around 1.30pm, I slipped off the trail and fell down a slope for 10 metres into the woods."
He could not find his way back to the trail.
"The trail was as good as gone. Everything, the trees, looked similar," said Mr Sanjay.
His shorts had also been torn in the fall so he decided to take them off.
"There was nobody to see me anyway," he said with a laugh.