Medea, daughter of the king of Kolhis, helped Jason (leader of Argonauts) to take the Golden Fleece, married him and then she followed him over to Corinth, where she bore two sons. But some years passed and Jason arranged to marry the king's daughter, so that he could be the next king in Corinth.
The king himself, Creon exiles Medea and her children from Corinth as he is afraid that she will try to take revenge out of spite. She implores him not to send her in exile or even to delay it and promises to be good. She manages to win a day before she has to leave.
While she is trying to figure out what her chances are for taking revenge but also be safe, she meets the king of Athens, Aegeus. He learns her hardship and promises to give her shelter, without knowing her vengeaful plans.
Medea puts her plan into action: she poisons a bride's veil and a golden crown and sends them with her children as a sign of reconciliation to the future bride. When the princess, Glafki, tries them on, she gets surrounded by a magic fire and dies in agony. Her father, the king tries to save her and has the same fate. The news come to Medea by a messenger. She is overwhelmed and procceeds to the last part of her plan, which is to kill her children, so that Jason will be left without a heir.
Jason arrives to protect his children from Corinthians' rage (as the children had given the fatal gifts), only to find then already dead, slaughtered by their own mother. Medea escapes in a flying charriot sent to her by her grandfather, the god Sun, leaving Jason desperate.