I have no idea what I'm doing, but it won't leave until I do it. So here goes.

Hercules was tasked by the goddess Juno to collect three golden apples that were found only in the garden surrounding Atlas, the giant tasked to hold up the sky, and guarded by Cerberus, a giant three-headed dog.
And so Hercules went to the garden and came across a tree bearing golden fruit, and Cerberus. He immediately threw himself at the beat but found all three heads snapping at him all at once and he was thus forced to run as fast as his bloodied body could. He did not know how far he ran nor where he was but when he looked back he saw neither head nor hide of the beast; and when he looked forward he saw a huge man, kneeling in a clearing as if he was holding something of immense weight on his back.
Hercules came closer and saw the man's eyes were shut. He decided to wake him up and did so by shouting at him.
The giant's eye slowly opened and he said, "Who are you to interrupt me in the middle of my task?", as if every word was a great effort.
Hercules responded by shouting, "I am Hercules, and I have come here looking for three golden apples to give unto the wife of Jupiter, Juno!"
The giant looked surprised at the mention of the golden apples, but became chiding when he noticed Hercules' lack of said apples. "And you seem to have found them, but were unable to defeat Cerberus."
"Yes. That is correct. How do you know this?"
The giant shrugged into a more comfortable posture that made the entire heavens shake. "I know this because Cerberus is mine. And that he is shackled to the tree from which the fruit is grown." He paused to stare into the eyes of Hercules a little harder. "Would you like for me to get these apples for you?"
"In exchange for what?"
The giant then laughed the laugh of one who had forgotten how to laugh, short, breathless, deep and with no joviality behind it, that again shook the heavens; but less so than before. "You can obviously see that I carry a great burden. Inherit it for me and I shall collect these apples for you. I know where the tree is, and Cerberus will not attack his master."
Hercules thought about this and thought it was simple task. His strength was boundless but his skin was not impenetrable and he was not fast enough to dodge Cerberus's bites. All he had to was hold this weight for as long as it took for this man to find the apples and return and he could go onto his next task. Besides, he looked like he had been holding this invisible burden for quite some time, and he pitied him for this; the least he could do was take his burden for at least a while. He told the giant he agreed to this deal.
And so Hercules held the sky upon his shoulders whilst the giant left to collect the golden apples. When the giant returned Hercules asked him to take his burden back, but the giant refused. He said that he had missed this freedom and would never relinquish it. But in return he thanked Hercules and promised him that he would deliver the apples to Juno as well as explaining to the Gods how he had taken mercy on Atlas and inherited his punishment of holding the sky up.
As Atlas walked away with the golden apple tree slung over his shoulder Hercules hurled insults after him until long after he could not be seen. After a while Hercules decided to wait for the Gods to realise Atlas' deception and rescue him. And he waited whilst he felt the sun descend and the moon rise. And he waited whilst the moon descended and the sun rose. And he waited whilst this cycle repeated until this cycle meant nothing anymore. And he waited until a silent heart kindled into a silent inferno in his heart that could be seen in his eyes.

And there he is to this very day, waiting for someone else to take pity on someone so obviously an enemy.