When Acrisius, King of Argos, heard that his grandson, the son of Zeus , was going to kill him and become the ruler of Argos, the king threw Diane and her son into a box at sea, intending to never see them again.
Diane was found by the fisherman Dictys, who offered Diane protection from his brother,King Polydectus, from her father.
The king instantly fell in love with Diane after seeing her beauty, but he had to get rid of Perseus, who was always in the way. So, when he gets older,he sends him to kill Medusa, a fierce, scary monster and anyone who looks at her turns to stone
Since Perseus could not look at Medusa directly, he used the shiny shield, a gift from the gods, to slay the monster.
On his way home, he sees a princess named Andromeda about to be killed by sea monster sent by Poseidon for insulting him. He kills it with Medusa's head and they get married.
He comes home to find his mother about to get married to King polydectes. Using the head, he kills Polydectes and the rich people of the city, and appoints Dictys as king. Later on in his life the prophecy comes true and he kills his grandfather in olypic games.