A grateful family are hunting for the mystery hero who stepped in to save their son from drowning.
Jackson Gardiner, 9, was pulled from the water at Fiddleford Mill, Dorset, last Wednesday.
His dad James, who can't swim, says the boy was swept away by the current and it 'scared the absolute life' out of him.
But after tracking down one of the people who helped drag him to safety, they want to find the second person and thank them for what they did.
The elusive stranger dived into the water to rescue to the child, Dorset Live reports.
James said the heroics probably saved the life of Jackson, who has ADHD and autism.
"It scared the absolute life out of me, to be honest," said the dad from Yeovil, Somerset.
"We'd actually been down there a while that day, they'd been playing in a shallow area that felt really safe at the time.
"They wanted to move up onto a little bridge area so we did that. Jackson went to sit down and as he did he slipped, landed on his bum and went straight into the water line.
"He went straight under and the current had him 20 feet away in seconds."
Jackson was caught on camera moments before slipping out of reach.
He was having fun and enjoying the initial water slide, not realising at first the danger of what was happening.
But at that point James reacted on instinct, recognising the risk.
"I jumped straight in after him, instinctively as a parent - I can't swim, so I started struggling and almost drowning.
"As I was managing to get myself out, I could just see this gentleman swimming out to Jackson.
"I was shouting at him to get on his back and float, as that's what they tell you to do."
"The guy got him out and just said 'well done, you did the right thing, and you didn't panic'.
"At the point part of me wanted to ask for his name and to thank him properly but my priority was also Jackson. He was in shock, and I was in shock, and I just wanted to get him home and checked out."
James says Jackson turned out to be ok and recovered quickly from the frightening near miss.
"He's recovered quickly, he was very shaken that day and for the day afterwards, but since then we have been swimming again, so it's not put him off.
"It probably traumatised me a bit more as a parent, I think. It makes you want to raise a bit of awareness.
"These places look peaceful and safe but they can be deceptive. It only took one second and Jackson was gone.
"I was right next to him but I couldn't grab him in time."
Jackson and brother Elijah, 5, both have life jackets now and are more aware of the dangers of the water. Both boys have been having swimming lessons for a few months.
While wild swimming is growing in popularity, it is always a risk, particularly with children and in areas without lifeguards - something James wants to raise awareness about with other parents.
But the whole family, from the Barwick and Stoford area of Yeovil in Somerset, still want to thank their mystery hero, who they think has a military background from brief words exchanged on the day.
James explained: "We've managed to find the gentleman who helped pull Jackson out from the river bank but we've had no luck finding the man who actually jumped in to save him."
What would James say to him, if given the chance?
"I would obviously just say thank you, firstly. I know Jackson would also like to say thank you again, too.
"I dread to think what would have happened if someone hadn't been there to jump in and rescue him."
