There was once a king named Acrisius, who ruled the city of Argos, in Greece. He was powerful and rich, but he had only one daughter, Danaë, and no son to inherit his throne.

"Will I have an heir?" Acrisius asked the Oracle of Delphi, the sacred temple where a priestess spoke the prophecies of the gods.

The Pythia fell into a trance and spoke with a voice that was not her own. Acrisius would have no son. But his daughter would have a son, and that grandson, one day, would be the cause of the king's death.

Acrisius went cold with horror. His own grandson would kill him? He would never let that happen.

Then Acrisius had a terrible idea. If Danaë never married, she would never have children, and without a grandson the prophecy could never come true. He had a bronze chamber built, an underground room with walls of metal, and there he locked away his own daughter.

Danaë wept and begged.

"Father, please, don't shut me in here!"

But Acrisius would not turn back.

"It is for your own good," he lied. "And for the good of the kingdom."

Danaë remained shut in the bronze chamber. Only a small opening in the ceiling let in light and air. Servants brought her food, but she could not leave. The years went by, and Danaë lived alone, gazing up through the opening at the distant sky, dreaming of freedom.

But from the heights of Mount Olympus, Zeus, the king of the gods, was looking down at the Earth. And he saw Danaë, beautiful and lonely in her prison, and fell in love.

Yet how could he visit her, when the bronze chamber had no door and its walls could not be breached? Zeus used his divine powers and turned himself into something that could pass through the small opening in the ceiling: a shower of gold. Bright golden drops came down through the opening, and Danaë watched in wonder as that light danced around her. It was Zeus, visiting her in magical form.

And from that divine visit, Danaë came to be expecting a baby. The child she carried was the son of Zeus, the king of the gods.

Months later, Danaë gave birth to a beautiful, healthy boy, and she named him Perseus. For a while she managed to keep him hidden. But babies cry, and one day Acrisius heard crying from inside the bronze chamber.

"Impossible!" he roared, ordering the chamber opened. "How do you have a baby?"

"Zeus visited me," said Danaë calmly, holding Perseus. "This is the son of the king of the gods. Your grandson."

Acrisius went pale. The prophecy. The grandson who would kill him had been born. But the child was the son of Zeus: if the king harmed the baby with his own hands, Zeus would destroy him.

"I cannot kill them," Acrisius muttered. "But I cannot keep them here either."

And he had another terrible idea.

Acrisius had a great wooden chest built, almost a little boat. He placed Danaë and baby Perseus inside it.

"If the gods truly protect this child," he said coldly, "let them save them."

And he ordered the sealed chest cast into the sea.

Danaë held Perseus tight against her as the chest slammed into the waves. Water seeped through the cracks, and everything rocked and pitched.

"Please, Zeus," she prayed. "You are this child's father. Save us."

And Zeus heard. He calmed the seas, and Poseidon, lord of the oceans, made a gentle current that carried the chest safely across the waters. For days it floated. Danaë nursed little Perseus, a soft rain gave them fresh water, and fish leapt into the chest, bringing food. Until, at last, the chest reached the island of Seriphos.

A humble fisherman named Dictys was out at sea when he saw the chest bobbing on the water and pulled it in with his net. When he opened it, he was astonished: inside were a woman and a baby, soaked, but alive.

"Who are you?" he asked kindly.

"I am Danaë, princess of Argos," she answered. "And this is my son, Perseus. We were cast out by my father."

Dictys was kindhearted.

"Come and live in my house. I will care for you as if you were my own family."

And so Perseus grew up on the island of Seriphos. Dictys treated him like a son, and the boy learned to fish, to swim, and to be brave and good. The years passed, and Perseus became a strong and handsome young man. He did not yet know he was the son of Zeus, but there was something special in him, a natural strength and nobility.

But there was a problem on the island of Seriphos. Polydectes, the king of the island and brother of Dictys, saw Danaë and wanted her as his wife.

"Marry me," he demanded.

"No," Danaë answered firmly. "I am grateful for your hospitality, but I do not love you."

Polydectes was furious, for no one refused him. And there was an obstacle in his way: Perseus. The young man, now strong, protected his mother.

"My mother said no. Respect her decision."

Polydectes came to hate Perseus. If he could only get rid of the boy, he thought, Danaë would be alone and would have to accept the marriage. And so the king devised a spiteful plan.

Polydectes announced that he was going to be married — which was a lie — and invited all the nobles of the island to the betrothal feast. Each guest was to bring a gift: a horse.

The rich men of the island had horses to spare. But Perseus and Dictys were humble fishermen and had none. Perseus, proud, went to speak to the king.

"My lord, I have no horse to give. But I will bring any other gift you desire."

Polydectes smiled to himself. It was exactly what he wanted to hear.

"Any gift?"

"Any at all," Perseus promised, without thinking.

"Then," said Polydectes slowly, "bring me the head of Medusa."

The whole hall fell silent. Medusa. One of the three Gorgons, terrible monsters with serpents in place of hair. The Medusa whose gaze turned any person to stone. It was a mission of death: no one who had gone looking for her had ever come back.

Dictys pulled Perseus aside.

"Do not accept. It is a trap. Polydectes wants you dead."

But Perseus was young, and he had given his word.

"I promised. I will bring back the head of Medusa, or die trying."

"My son," said Danaë, weeping, "no one survives Medusa. One look, and you become a stone statue."

"Then I will not look at her," Perseus answered, resolute. "I will find a way."

That night, Perseus went to the shore to prepare for his journey. He had no weapons, no plan, and did not even know where Medusa lived. But he had something he was only beginning to understand: the blood of Zeus ran in his veins, for Danaë had finally told him the truth. When the sun rose, he lifted his eyes to the sky.

"Father, if you really are Zeus, if I really am your son, help me now. I need guidance for this impossible mission."

And Zeus heard. The story continues in Part 2, when Perseus receives the help of the gods, faces the strange Graeae and, at last, meets Medusa.