Tell you what, I bring back medusa head and you will stop stalking my mum
Years later Perseus grew up to be a strong and brave young man. But over time things got a little complicated. King Polydectes continuously pushes Danae to marry him. But Perseus was a very protective and stubborn boy and wouldn't let Poyldectes near her or touch her.
Give me the Nymphs Location or I'll sabotage your eye
So the only way for Poyldectes to get to Danae was to trick Perseus that he was going to marry another wife and that Perseus had to pay at tribute as part of tradition. So as determined as he was, he swore he would bring back Medusa head. The King accept his offer but warn him that if he failed he would take his mother by force.
Along the way he was assisted by both Athene and Hermes. They are willing to help him in exchange for slaying Medusa. Athene offer him a shield as protecting from Medusa glaze, and Hermes offer him a Sickle to strike Medusa down.
The Gods reminded Perseus that he needs to retrieve three artefacts from the Nymphs, which only the Graeae know where to find them. So Perseus located the Graeae and demanded the location of the Nymphs by holding their eye hostage.
After that episode, Perseus was able convince the Nymphs that he needed these artefacts for some really important mission, that even the Gods demand it. These artefacts include, a pair of winged sandals, an invisible cap and a bag to which to carry Medusa’ head.
Using the winged sandals Perseus flew to the lair of the Gorgons. Hidden through his invisible coat and holding his shield, Perseus swang his Sickle slicing Medusa head clear from her shoulders. As she died, from the roots of her neck, came the birth of Pegasus and Chrysaor, her two offspring of Poseidon.