The story of Medea is only one part of a myth about the Argonauts' campaign. It portrays Jason joining a battle with fire-breathing bulls and a dragon guarding the Golden Fleece, Medea is helping him tame the beasts. She then follows him to Greece, because she falls in love.
It is also a story of how a once young, beautiful and joyful woman, transforms into a monster, hungry for revenge, she kills even her own children. A long trail of horrible deaths, tied to her life path, is hard to imagine.