After perseus had promised to bring the head of medusa, he went to a cliff overlooking the sea, and asked the gods for aid on how to find medusa. Hermes came down and told him the location of the gray sisters, across vast seas and land, who can help him find medusa, and also gave him winged shoes enchanted by Athene that flew as swift as an eagle.
Perseus flew over oceans towns and mountains until he found himself over a sea of ice. He found the gray sisters and snatched their one eye and tooth. Perseus told them if they didn't tell him where to find the nymphs of the west, he would crush the eyeball. Under quick consideration the gray sisters had revealed where to find them, and Perseus set off.
Perseus found the 3 nymphs, who tried to convince him to party and stay. Perseus promised with their help he would come back after his quest was finished. So they gave him the location of medusa and 3 gifts that would aid him during the fight. The items were a bronze shield that would act as a mirror, a sickle like sword bright as the moon, and the cap of darkness which would make him disappear when he put it on.