Acrisius, King of Argos came home from Delphi with a heavy heart. The Oracle told King Acrisius that he would have a grandson that would kill him, so he locked Danae in a tower so she should never marry.
A son was born to Danae, the father was Zeus. Danae had a child anyway, so Acrisius put Danae and the baby to the chest. Then, Acrisius pushed it out to the sea.
The chest washed up on the shore of Seraphos. King polydectes heard about them and wished to marry Danae, but she refused. In order take her by force he needed Perseus away, because Perseus always guarding her. King Polydectes held a feast and invited all young men. All of them brought presents except for Perseus, so the King tricked Perseus into getting him a gorgon's head.
Athena and Hermes came, they gave him the sharpest weapon and a shield so he could see Medusa without being turned into stone. Then they told him to visit the Gray Woman for the location of Nymphs, which he can get the winged sandals, magic wallet, and helmet of invisibility.
He saw Medusa, Perseus swing widely his sword. He felt the sharp steel bite into flesh and bone. Then at last it was over, he is not looking at Medusa. Perseus picked up Medusa's head and put it on the magic wallet.
On the way home, Perseus rescued Andromeda and brought her back to Seraphos. He turned the king into stone using Medusa's head. Perseus turned over the throne to the old king's brother. Then he went back to Argos, but Acrisius had already escaped a few years ago. So, Perseus took his place as the rightful king of Argos.