Six firefighters scaled the North Island's four highest peaks within 24 hours - finishing the challenge with just 20 minutes to spare.
Mountains for Mito - Four Peaks was organised by Tauranga firefighter Kevin Cowper after learning that Mitochondrial disease had affected one of their own.
Maddox Parker, the son of fellow firefighter John Parker and his wife Rebecca, was diagnosed with the disease and died on November 17 aged just 23 months.
After learning of their story, Mr Cowper organised the fundraiser to help raise awareness and money for the cause. The Parkers want to raise $1 million which would go directly to Starship children's hospital for Mitochondrial disease.
Everybody felt really good after the first one, everybody was on a high and buzzing because of the view, the sunrise and all of that.
The group of six firefighters from Tauranga and Kawerau fire brigades started their journey on Monday, walked up and down Mount Taranaki, Mount Ruapehu, Mount Ngauruhoe and Mount Tongariro and completed the mammoth walk just inside the 24-hour challenge they had set for themselves.
Starting at 3am, it took the team three and a quarter hours to get to the top of Mount Taranaki where a beautiful sunrise greeted them on their arrival.
"There wasn't a cloud in the sky, it was beautiful. So we had a photo, hopped back down the mountain and we were driving out about 9am."
They arrived at Mount Ruapehu and scaled it in the same time as Taranaki. They started climbing Mount Ngauruhoe at 8pm that night and were lucky they had taken a GPS with them as cloud set in across the mountain overnight.
By 2.40am on Tuesday morning they reached the summit of Tongariro exhausted but elated they had made the forth peak in the 24 hours.
Mr Cowper said the team kept each other motivated through the four peaks.
"Everybody felt really good after the first one, everybody was on a high and buzzing because of the view, the sunrise and all of that. Same after Mount Ruapehu, everyone was still feeling pretty good. Once we hit the clouds and steepness of Ngauruhoe, it was really hard climbing because it was all scoria. It would be fair to say the enthusiasm levels dropped considerably. Having said that, there wasn't one word of not doing it.
"We knew that if we couldn't carry on and finish it we would have to go back to the start and do it again and nobody wanted to do that."
The six hikers only came out of the excursion with blisters, sore muscles and exhaustion.
It was all worth it, he said.
- To donate to the cause, please visit www.fundraiseonline.co.nz/MitochondrialDisease/
What is Mitochondrial Disease?
* Mitochondrial disease is a chronic, genetic disorder that occurs when the mitochondria of the cell fail to produce enough energy for cell or organ function.
* Mitochondrial disease is inherited in a number of ways. There may be one individual in a family or many individuals affected over a number of generations.