King Acrisius locked his daughter Danae in a tower to prevent the prophecy that her son would kill him. However, Danae gave birth to Perseus. Acrisius cast them into the sea, but they survived and ended up in Seriphos. There, King Polydectes wanted to marry Danae and tricked Perseus into getting Medusa's head. With help from the gods, Perseus killed Medusa and rescued Andromeda from a sea monster. He used Medusa's head to turn Polydectes to stone and became the new king, inadvertently fulfilling the prophecy by later killing Acrisius.