At the noon of the next day, Hercules was crossing the forests of Lerna. He was silent and seemed to be lost in his thoughts, although he was not alone. His nephew Iolaos, walking beside him, asked reluctantly: "Are you sure the King will not punish me for assisting you in this trial, uncle?" Hercules smiled briefly. "I will offer myself to be punished in your place if need be. In any case, I need your help with this spawn of Typhon. The Hydra of Lerna is said to be immortal and has lived in the Lernaean Swamp for more centuries than man can remember."
The two men approached the swamp with great caution and they soon spotted the hydra. The beast was huge, its nine heads towering over the nearby treetops. Hercules wasted no time; he asked Iolaos to light his arrows with the torch he was carrying. His nephew promptly obeyed and soon a hail of burning arrows met the monster's body. The Hydra made terrifying sounds of pain and tried to escape their sight, but Hercules quickly ran and jumped on its back. Soon he was cutting its heads one by one with a sickle he was carrying, but he was surprised to notice that for every head he removed, two sprung in its place. Suddenly, the hero felt a sharp pain on his leg; for a giant crab had assisted the monster and pinched his thigh with its claw. However, Hercules didn't lose his temper and asked Iolaos to quickly hand him the torch he was carrying. The hero then proceeded to burn the Hydra's heads, preventing their regeneration and when there was only one left the burn-proof and immortal one, he had that one buried under a huge rock.
Tired but victorious, the hero and his helper left the swamp and headed back to the city of Tiryns. Eurystheus greeted them with a grin. "Hercules, dear cousin, you should have asked me before employing help from someone else. I deem this victory unlawful, for you have not followed the rules already set by me and you have improvised instead, effectively ignoring my authority. There are still eight Labors to be done by you before your penance is due." With these words, the King left and the two heroes gave each other a troubled look.
Deep in the night, at Hercules's camp, Iolaos woke up by his uncle's voice. He was growling deeply and moving erratically in his sleep. What was he dreaming of? Iolaos wondered. In his dream, Hercules was battling the Hydra once more. But this time he was on the losing side, for the Hydra was being assisted by his own shadow-self. The Hydra's mouth spit its poison on him and the hero felt like a flame was burning his body away. The shadow stood there and watched, as Hercules was twitching in agony. "This is the poison of desire, meant for heroes and cowards alike. It fuels every one of your mishaps and makes me whole, son of Zeus.’’ ‘‘Hercules. Hercules!" The hero woke up abruptly. Iolaos was standing over him with a troubled look on his face. So this was just another of those strange dreams, Hercules thought.