Polydectes fakes a marriage with a princess so the people of the land must give him a gift. Perseus had nothing to offer as he was too poor. Polydectes then proposes a gift that Perseus can win for him. The head of Medusa.
Give me that snake hair lady head.
Luckily, Athena hears of this news and sends Hermes to help Persues out with his journey. Hermes then gifts Perseus a sword to cut Medusa's head.
I am here to help
First, they had to go to the Gray Women that will show them the way to the nymphs which will give Perseus gifts to defeat Medusa. But first, Perseus must steal the eye of the Grey Women to show him the way to the nymphs.