Gus Taylor is where he's happiest, hooked to a rope, climbing in the Blue Mountains. Then a rock comes loose under his foot.

Below him, belaying the rope, is his mate Richard "Millsy" Mills, an easy-going Kiwi who's made Sydney his home. He's the life of the party, a "legend of legends". And a first-time climber.

Gus screams "rock". Richard ducks his helmeted head forward, and the brick-sized rock smashes onto his back.

He crumples over but, despite his agony and failing consciousness, holds onto the rope. To let go would see Gus, now dangling free of the cliff, fall seven metres.

"The bastard was still holding the rope," Gus tells Australian Story, shaking his head in awe at his mate's valiant act. "You know, he couldn't move."

Somehow, Gus manages to swing back to the cliff, untie himself, and free climb down to Richard.

"I quickly realised the situation that we were in and just gave him a big hug," Gus says. "I tried to make sure that he felt comfortable and that I was there for him and that everything was going to be okay.

"And in my mind, everything was going to be okay. There was no way in hell that we weren't going to get out of there and he was going to get looked after."

But the wind had picked up, making it unsafe for a helicopter rescue. A doctor from another group on the Sweet Dreams climb, a busy route popular with beginners, came to help. Paramedics had to walk in, then abseil down. And the hours ticked away.

"But the paramedic just kept saying that he wasn't stable enough to do anything.

"Millsy's breathing got really bad and I leant down to give him a hug and just said, 'I'm so sorry'. And he looked at me and he said, 'It's cool. It's cool, man.' And just smiled.

"And that was the last thing he said."

Richard Mills, 36, died later that day, November 20, 2022, on the operating table. And Gus fell into a "very deep hole".

He blamed himself. Everyone told him it was a freak accident, even Richard's parents, Mary and Oscar, who came out from New Zealand and wrapped their arms around Gus in their shared grief.

"I was in a pattern of self-blame and they were doing a lot to help me past that feeling," says Gus, now 34. "But it is something I've found hard to accept."

For a long while after the tragedy, Gus says, just thinking about climbing "revolted me". But, in time, a voice penetrated through his depression.

"It was basically Millsy, telling me to get on with it," Gus says. "Being in a hole wasn't what he wanted, it's not how he would have lived his life. He was the complete opposite, squeezing the lemon, making the most of absolutely everything in front of him. And I felt like I was dishonouring that."

'I just wanted my life back'

Gus Taylor's relationship with rock climbing is a complicated one. "It's given me everything and taken a lot away," he explains.

Five years before Richard's death, the unforgiving force of gravity had already dealt Gus a shocking blow. He'd fallen from a boulder at California's Joshua Tree National Park, on the last day of an eight-week climbing trip, damaging his left leg terribly.

"It took me a couple of seconds to realise that the screams I was hearing from Angus weren't frustration," says his travelling companion Josh MacKenzie. "They were pain, fear, injury."

Josh bolted to Gus's side. His bones were jutting out through his jeans. "My leg was spaghetti," Gus says.

For almost three years, Gus and his surgeon battled to save his leg.

There were pins in it and a frame around it, stitches that opened and ushered in infection, a skin flap "that looked like a deli sausage," infection in the bone, yet another operation to harvest bone, and the acute pain from trying to bear weight for weeks on a leg that, unbeknownst to Gus, had re-broken. Finally, Gus decided to have his leg amputated.

"I just wanted my life back," Gus says "I couldn't bear the pain anymore. I was low. Really low."

It was such a long way from the "intoxicating, unadulterated freedom" Gus had enjoyed during that US climbing trip. He and his mates would get in the van, loaded with camping and climbing gear, and set off with music blasting as the cliffs rose into view.

The obsession begins

Music has always been important to Gus. His stepdad Russell, who married his mother Sue when Gus was three, is a drummer and introduced him to bands such as Led Zeppelin, the Smashing Pumpkins, and Powderfinger.

They moved around NSW a lot, and in year nine, Gus found himself in Parkes, in central NSW, struggling to fit in. Then Russell bought him a drum kit and everything fell into place.

"I remember standing up at [our] house on the hill … and I just saw these kids riding their bikes down the road and they all jumped the fence and started walking up the paddock. And they just invited themselves in," Gus says. "They were just like, 'We heard you had a drum kit'."

They jammed their way through high school, and soon after graduating, the band, Bears with Guns, was formed. Recording contracts followed, then national tours, including an "absolutely incredible" time supporting Icehouse, and a lap around New Zealand. But after five years, Gus decided it was time to hang up the drumsticks.

His recent marriage to long-time girlfriend Rosie was rocky and he'd discovered a new obsession — climbing. He threw himself into it and, as his marriage ended, his love for the climbing community grew.

"It's one of the most open and supportive communities I've ever had the privilege of being a part of," Gus says. "Any time I was going through something really hard, they were the net that I fell into."

How Millsy saved Gus

Gus's long climb back to embracing life after the amputation was tough but the tragedy of losing Richard Mills was another level of pain. Gus wished he'd died up there.

"I didn't feel like I deserved to be around," he says.

Not for a moment did Richard's parents feel that way. Recalls Mary: "I said to him, 'But if you had died, you wouldn't have been there to look after Millsy. And we're so grateful that you were with him and looked after him like you did'."

The family cherishes the fact that Millsy was revelling in the climb before the accident – and that his final act was to hold onto that rope. "Millsy saved Gus's life," says Mary. That strength and selflessness of their charismatic son, says Oscar, is something their family will hold onto forever.

Gus is still working on forgiving himself. "That's the end goal. I think I'm getting a little piece every day. I'm trying."

Therapy has helped. Once Richard's voice pushed through Gus's fog, badgering him to get on with life, he sought out rapid eye movement therapy, or EMDR, and found it effective. "I was starting to walk away feeling lighter."

Eventually, his therapist told him it was time to head back to the cliffs. "He said, 'There's one thing we can't confront unless you confront it yourself. And that's climbing'."

On the day, Gus was uneasy, expecting to react badly. "Instead," he says, "it was like reconnecting with myself, like plugging in a lamp." He didn't climb that day, but the next weekend, someone offered him a rope. "The moment I pulled it on…it was like a weight had lifted and I just felt like me. Funny thing, climbing. I mean, hate it and love it."

Back when Gus was wrestling with the tough decision to have his leg removed, his surgeon joked that Gus might even be a Paralympian one day. Now, after encouragement from the paraclimbing community, that's his goal.

Late last month, Gus competed in the Paraclimbing World Cup in Arco, Italy, ranking top 10 in his category. Come 2028, he hopes to climb for Australia at the Los Angeles Paralympics.

"Climbing has this way of moulding itself into the thing I've needed at the time and being somehow the most helpful thing for healing and growth," he says.

Gus knows the bulk of people can't understand the compulsion, what drives people to scale sheer rock faces, risking everything for the summit. 

He recalls the words of Warren Harding, a pioneering big wall climber, who, on descent from leading the first team to climb El Capitan in the US's Yosemite Valley in 1958, was asked the question, "Why?" He replied: "Because we're insane."

Says Gus: "It does sum it up to some degree. You have to be a type of person to find joy or pleasure in suffering because you do have to suffer for it. But, in a way, the most rewarding parts of life are the things that you make some level of sacrifice for, the things you must work for. They're the things that really make you feel like you're alive. At the end of the day, that's how I want to feel.

"So, are we mad? Maybe. But maybe the right kind of mad."

Watch Australian Story's 'Holding On', 8:00pm, on ABCTV and ABC iview.