Some people believe everything happens for a reason. But the fact that this man chose to explore this particular canyon on this particular day beggars belief.

Zachary Anderegg lives for adventure. He can often be found hiking the Arizona and southern Utah slot canyons. Yet on one such adventure he made a discovery that would change his life forever.

It was June 20, 2010. Anderegg was exploring a slot canyon in northern Arizona. It was something he often did, sometimes with family, sometimes alone – like this time.

Anderegg had embarked on what was a relatively easy hike for a man of his capabilities. It was a dry, bright morning, perfect for a day of exploring.

As the hiker continued deeper into the canyon, the gap between the walls narrowed, almost entirely blocking out the sun at some points. Nevertheless, he made his way along the bottom of the gorge before descending down a small drop.

Down in this region the canyon walls began to open up again, letting in more light. Here, Anderegg ventured along a corridor and into an opening, which he described as being like “a really neat room.”

The climber had reached a depth of around 100 feet. But he was going to go much deeper. So he rappeled down a steep incline, and this led him into a pitch-black pass.

Anderegg now reached a second drop of around 20 feet. And using boulders to secure his climbing gear, he set up to make a further descent. What he found at the bottom of this drop, though, was something he was completely unprepared for.

Deep down, at around 350 feet below the canyon’s edge, was a dog, trapped. Lying beneath a crevasse which Anderegg reckoned was too deep for it to have survived falling from without breaking bones, the dog seemed to have been deliberately abandoned and left to die.

Anderegg immediately left the canyon, later returning with a towel, food and water for the skeletal dog. But it wouldn’t be until Monday that he could return with adequate rescue gear to haul the dog from the pothole.

Convinced that the animal didn’t have long to live, Anderegg prepared to abseil directly down the rock face to make the rescue. With the hiker having seen the terrible state the dog was in, he knew he needed to act fast and get him to a vet before it was too late.

Armed with nothing more than a cat carrier from a local animal hospital – the fire and police departments had told him that they were unable to help – Anderegg was on his own, but he was determined. “When I saw him my heart just absolutely broke,” he said to Today.

The puppy was in a very bad way, though. He was emaciated and, Anderegg was certain, barely clinging to life. Delicately placing the dog in the crate, then, the rescuer hoisted the weak animal to the surface and rushed him to hospital.

The dog would spend the next day and night at the animal hospital. It was there, too, that the full extent of his abuse became apparent. Shotgun pellets were found embedded in his flesh, and his teeth were blackened from malnourishment.

Affectionately nicknamed “Puppy,” the dog was incredibly weak. But with the help of doctors, Anderegg, his wife Michelle and a few friends took turns in caring for the pup while the search for a new home began.

Puppy was in such a bad way that even when he left the vet he was still too weak to stand. When Anderegg took him home, however, the rescued dog mustered enough energy to wag his tail. Anderegg took this as a sign that things were going to be okay.

With lots of love and affection, day by day Puppy grew stronger. And so too would the bond between the dog and his rescuer. In fact, he was renamed Shadow owing to the close quarters that he kept with his new human companions.

While looking for a new home for Shadow, Anderegg and his wife soon came to realize that they couldn’t give him up. Indeed, with Anderegg believing that their encounter had been destiny, the dog – now named Riley – went on to inspire his new owner to write a memoir. Meanwhile, the amazing story of the rescue spread far and wide and would lead to television appearances on the Today Show and the Ellen DeGeneres Show.

Anderegg believes Riley was placed on a path in order to save his own life as much as he had saved the dog’s. Anderegg’s own personal, emotional canyon was carved out during a childhood spent at the mercy of bullies.

Along with the dog’s new brother Kohi, Riley and Anderegg have now left their abusive pasts behind them. The three regularly undertake adventures together with Michelle, exploring the canyons and lakes of Arizona and Utah.

Riley is now a happy and healthy dog – and even has his own Facebook page. Anderegg wrote on it, “He has become a cherished member of our family. He is without doubt one of the sweetest dogs I’ve ever known.”