Geryon was a reclusive giant that lived in the west, far beyond the boundaries Heracles had normally ventured. He possessed, in some accounts, three bodies and was a fearsome opponent in battle due to this. 

The journey, however, was to be the main challenge for Heracles. He was forced to wander through the harsh warmth of the Libyan desert, bedevilled by a heat so great that he ended up firing an arrow at the sun. The sun, Helios, gave Heracles the cup which he uses to ride across the seas each night. Using this cup, Heracles ventured to Erytheia, the island of Geryon. It is said that Oceanus, the ancient Titan of the sea which surrounds the world, attempted to intervene, as Geryon was a descendent of his, But Heracles made threats via his bow which forced the Titan to give up. 

Upon arriving, Heracles was accosted by Orthus, a two-headed dog, and Eurytion, a herdsman. Heracles dealt with the two easily but the ruckus alerted Geryon who prepared himself with a set of armour and weaponry for each of his three bodies. Much the same as Orthus and Eurytion, Heracles dispatched the giant with ease by using one of his poison arrows. 

It was then the task of Heracles to herd the cattle, a task often made complicated by Hera, who conspired constantly against Heracles. Hera used a gadfly to separate the herd, which forced Heracles to then retrieve them. This took an entire year. Hera then flooded a river which meant that Heracles was barred from bringing the cattle across. Heracles, always inventive, piled rocks to form a bridge. Finally bringing the cattle back to Eurystheus, he had completed his tenth labour.