When Perseus asked Zeus for help, the gods answered.

First came Athena, the goddess of wisdom, descending from Olympus in her shining armor.

"Perseus," she said, "you are brave, but reckless. You cannot simply go looking for Medusa unprepared. She will turn you to stone with a single glance."

"Then how can I defeat her?" asked Perseus.

Athena handed him her shield, polished like a mirror.

"Take it. Never look directly at Medusa. Use this shield as a mirror, and you will see her reflection without meeting her eyes."

"But I still need a weapon," said Perseus.

Then Hermes, the messenger of the gods, appeared on his winged sandals and gave him an adamantine sword, forged from the hardest metal there is, able to cut through anything.

"There is still one problem," said Hermes. "No one knows where the Gorgons live. They hide at the ends of the earth."

"Then how will I find them?" asked Perseus.

"Seek out the Graeae first, the Gray Women," Athena answered. "They are sisters of the Gorgons, and they know where Medusa is."

"And where do I find the Graeae?"

"At the far western edge of the world, where the sun never reaches," said Hermes. "But be careful: they are cunning and dangerous."

Perseus flew off on the winged sandals Hermes lent him. He flew over sea and mountains, beyond all the known lands, until he reached the place where the mist never lifts.

There, in a dark, damp cave, lived the Graeae, three sisters who had been born old. Their names were Enyo, Pemphredo, and Deino. They had hair white as snow, skin wrinkled like ancient parchment and, among the three of them, only one eye and one tooth, which they passed from hand to hand.

"Pass the eye, sister," screeched one.

"I haven't finished looking," grumbled another.

Perseus watched from a distance, wondering how he could make those creatures reveal where Medusa was. Then he had an idea. He waited for the exact moment when one Graea took out the eye to pass it to another... and he caught it in midair, before any of them could reach it.

"Where is the eye?" shouted one Graea.

"I had just passed it!" said another.

"You dropped it, you fool," accused the third.

The three groped blindly, searching for the lost eye.

"Is this what you're looking for?" said Perseus, holding the eye in his palm.

The Graeae shrieked, demanding the eye back.

"I will return it," said Perseus, "if you tell me where to find the Gorgons."

"Never," they hissed. "They are our sisters."

"Then you will stay without sight forever," Perseus answered calmly.

The Graeae grumbled among themselves and at last gave in. Enyo spoke: the Gorgons lived on an island beyond the river Ocean. But sword and shield would not be enough. Perseus would also need the sack of invisibility and the helmet of darkness, kept by the Nymphs of the North, at the far edge where the ice never melts.

Perseus returned the eye and flew north.

In the frozen north, Perseus found the Nymphs, beautiful, gentle spirits of nature.

"You have come for the sack and the helmet," said their leader. "Zeus told us you would come."

They gave him a magical sack, the kibisis, which changed size and could hold anything, even the head of Medusa. And they gave him the helmet of darkness, which belonged to Hades and made its wearer invisible.

"Now you have everything you need," said the nymph. "But remember: Medusa was once beautiful, like us, and she was cursed. Do not hate her. Pity her, and do what must be done."

Perseus set out for the island of the Gorgons, prepared at last.

The island of the Gorgons was a terrible place. It was covered in statues: people and animals turned to stone by Medusa's gaze. There were warriors frozen mid-attack, sailors petrified as they fled, even stone birds scattered on the ground.

Perseus walked carefully among the statues, invisible beneath the helmet of darkness, holding Athena's shield up as a mirror. And then he saw them: the three Gorgons. Stheno and Euryale were immortal and could not die. But Medusa, the one in the middle, was mortal.

All three were monstrous, with fangs of bronze, claws of metal and, instead of hair, living serpents that hissed and writhed. They were asleep. This was Perseus's moment.

Perseus crept toward Medusa slowly, looking only at her reflection in the mirrored shield. Even asleep she was fearsome. The serpents on her head hissed softly, and her fangs gleamed.

Perseus raised the adamantine sword. Guided only by the reflection, he brought it down. It was a single, clean stroke: Medusa's head fell.

The serpents hissed one last time, and the other two Gorgons woke screaming.

"Our sister! Who has done this?" roared Stheno.

But Perseus had already placed the head in the magical sack, taking every care not to look, and had put on the helmet of darkness. Invisible, he flew away, while the furious Gorgons searched for him in vain.

Perseus flew homeward, carrying Medusa's head in the sack. Even in death, her gaze still turned to stone anyone who saw it.

Flying over Ethiopia, he looked down and saw something strange: a beautiful young woman chained to a cliff at the edge of the sea. He came down and found Andromeda, a princess about to be sacrificed to a sea monster.

"Why are you chained here?" asked Perseus, shocked.

"My mother boasted that I was more beautiful than the Nereids, the nymphs of the sea," wept Andromeda. "Poseidon, furious, sent a monster to destroy our kingdom. The only way to appease him is to sacrifice me."

Perseus looked at her. She was truly beautiful, and brave: even facing death, she kept her dignity.

"No one will be sacrificed today," he declared. "I will fight the monster."

At that moment the sea began to boil in giant waves, and out of the waters rose the Cetus, an immense sea monster with teeth like swords and eyes red as embers.

"Run! Save yourself!" cried Andromeda.

But Perseus did not run. He flew straight at the monster, sword in hand. The Cetus tried to devour him, and Perseus dodged. The monster hurled jets of water, and Perseus climbed higher. Then he had an idea. He opened the sack and drew out the head of Medusa. Holding it by its serpent hair, turning his own face away, he pointed it at the monster.

The Cetus looked straight into Medusa's dead eyes. In that same instant, it turned to stone. An enormous statue of a sea monster sank slowly into the ocean.

Perseus broke Andromeda's chains and set her free.

"You saved my life," she said.

"And you touched my heart," Perseus answered. "Will you marry me?"

"I will," Andromeda smiled.

But there was a problem: Andromeda had already been promised to another man, her uncle Phineus. When Perseus arrived at the palace with her, Phineus appeared in a rage, claiming the princess belonged to him, and attacked with a hundred soldiers. Perseus fought bravely, but they were too many. So, once again, he used the most powerful weapon he possessed: he raised Medusa's head before Phineus and his men, and every one of them turned to stone.

Perseus and Andromeda were married. And at last, he set his course back to Seriphos.

When Perseus reached Seriphos, he found a terrible scene. Polydectes was forcing his mother, Danaë, to marry him, and old Dictys no longer had the strength to defend her.

"Polydectes!" Perseus thundered, striding into the palace.

"Perseus?" The king went pale. "Impossible. You should be dead."

"You wanted the head of Medusa?" said Perseus. "Here it is."

And for the last time, he drew the head from the sack. Polydectes and his cruel servants looked... and turned to stone.

Perseus made Dictys the new king of Seriphos. Then he set out with Danaë and Andromeda for Argos, his mother's homeland.

When they reached Argos, however, Acrisius, Perseus's grandfather, fled the city. He had not forgotten the prophecy: his grandson would kill him. Perseus wished his grandfather no harm at all, and even sought him out to make peace.

Years later, Perseus took part in athletic games in another city. He threw a discus, but the wind caught it, and the discus struck a spectator on the head, killing him. It was Acrisius, who had come to the games in disguise. The prophecy was fulfilled, but by accident. Perseus had never wanted it, and he wept for his grandfather. He learned, then, that fate cannot be cheated, only accepted with courage.

He returned the magical gifts to the gods. Athena took the head of Medusa and set it upon her shield, the Aegis, where it would protect the goddess forever. Perseus and Andromeda had many children and lived happily, always remembering the adventures that had brought them together.