King Acrisius was told by the nymph Delphi that he would be killed by his grandson who was the child of his daughter, Danae. So he locked her up under ground her whole life so she would never find love.
Whilst she was locked away she fell in love with the god Zeus. 9 months later she gave birth to a baby boy named Perseus because of this Acrisius sent his daughter and grandchild out to sea so he would not be killed.
When they arrived king Polydectus fell in love with Danae and he wanted to spend his life with her. As Perseus grew older he did not want his mother to marry the king so Polydectus decided to send him away to kill the monster that haunted the town; Medusa.
However on the way he was given gift to help him through his journey. He got the invisibility helmet of Hades, a shield from Athena and the winged sandals of Hades. The Gorgon cave was pitch black except for 2 glowing red eyes.
The hardest part of his quest was that he could not look at her in the eyes or he will be turned to stone. When the monster came up behind him, So Perseus looked at her reflection in his polished shield he got from Athena to see where Medusa was and cut her head off.
When he returned from his trip Perseus was greeted by Hermes and Athena. Athena held up the Gorgon's head in appreciation of the brave hero.