Mythology Part 3: Heroes Before the Trojan War, Chapter 1: Perseus
Argos' King Acrisius had a single daughter named Danae. He went to Apollo's oracle at Delphi. The oracle told him that his daughter would bear a son who would later kill him. Acrisius could not kill his daughter but he shut her up below ground. One day, a shower of gold fell through the opening and Zeus impregnated her with a son who would be named Perseus. Acrisius was indignant when he found out that his daughter was pregnant, and he put her in a chest with her baby and cast it into the sea. They drifted for a day and a night and landed where a fisherman found them and took them in. He and his wife cared for them for many years. When Perseus was full grown, Polydectes, the ruler of the land, wanted to marry Danae and decided to get rid of her son. He told Perseus that all he wanted for a wedding gift was the head of the mortal Gorgon Medusa. He knew that Perseus would go after the beast and die in pursuit. Hermes and Aphrodite took pity on the boy and helped him. He was given winged sandals and a hat that made him invisible. He was also given a sword and a mirrored shield he would use to look at the Gorgons (they could not be seen directly without the onlooker being turned into stone). He was also given a magic wallet that would expand to the size of whatever it needed to carry.
Perseus was guided to the Gorgons and he succeeded in killing Medusa. "But the two other sisters had awakened and, horrified at the sight of their sister slain, tried to pursue the slayer." Part 3, Chapter 1, pg. 204. He escaped them and went through Ethiopia where he rescued a woman named Andromeda from a serpent to which she had been offered. He took her to her parents and asked to be married. When they arrived back at his home, the fisherman and his wife were hiding in a temple because Polydectes was trying to kill them. Perseus entered Polydectes' banquet hall and pulled the Medusa head out of the bag. Everyone in the hall turned to stone. Perseus made the fisherman the king of the island and he headed back to Greece. When he got there, Acrisius was not in his palace. Perseus went to compete in an athletic competition. The discus he threw went awry. It hit and killed an old man in the crowd. The man was Acrisius. Perseus and Andromeda give birth to the grandfather of Hercules.