It started with a meatball.
Deep in the rainforest of Ecuador, four hungry Swedish athletes competing in the Adventure Racing World Championship were sitting down for a meal when they were approached by a stray dog.
One of them fed him a morsel.
As they stood up to carry on the race, the dog started to follow the team - and he didn't stop. He followed the team members for the last two stages of their 690km trek over land and water - dragging himself up hills and trekking through knee-deep mud to keep up with the team.
Before one of the segments of the race - a 57km kayak around the coast - organisers warned them that taking the dog along posed a risk to his and their safety.
So they tried to set off without him.
But as they left, he jumped into the water beside them and started desperately paddling.
Team Peak Performance captain Mikael Lindnord, heartbroken by the sight of the dog - which they named Arthur - struggling in the water, picked him up, put him in the kayak and let him stay for the rest of the journey, according to the Daily Mail.
The gesture prompted a standing ovation and cheers from spectators watching from the banks.
"The organisers advised us not to bring Arthur, as it could be unsafe on the water," he said. "But when we set off in the kayaks, he started swimming after us. It was too heart-breaking and we felt we couldn't leave him, so we picked him up.
"We could hear the people cheer on the shore as we set off."
After six days, the team finished the race and Arthur was taken to a vet in South America to be checked out.
Mr Lindnord decided to adopt him, introducing Arthur to his daughter and wife at Arlanda Airport in Stockholm when the team returned home.
Adventure Racing is a form of extreme sport that combines continuous hiking, trekking, mountain biking and kayaking over a successive number of days. The world championships held in Ecuador covered three diverse geographical regions - the Andes, the Pacific and the Amazon rainforest.
Mr Lindnord told Swedish news site Aftonbladet: "I had just opened a food pack, when I saw a scruffy, miserable dog in the corner of my eye.
"I thought he was hungry and gave him a meatball. Then I thought no more of it.
"I came to Ecuador to win the World Championship," he said.
"Instead, I got a new friend."