Act I
Ancient Corinth. Outside Creonte’s palace on the day before her wedding, Glauce, princess of Corinth, is preparing for her wedding to the hero Giasone. Yet on a day when she should be filled with joy, her overarching emotion is that of fear: For years, Giasone has been in a relationship with the sorceress Medea, the mother of his children. Glauce knows that Medea and Giasone have a long and complicated history—the sorceress used her magic to help him steal the treasure known as the Golden Fleece, murdered her own brother and Giasone’s uncle in her efforts to help him regain his throne, and ultimately accompanied him into exile in Corinth. Aware of this past, Glauce worries that Medea, who is still in love with Giasone, may do something to stop the wedding. Giasone promises Glauce that he no longer has any interest in Medea, and preparations for the wedding feast begin. The celebrations are interrupted when Medea appears and demands that Giasone return to her. Giasone rejects Medea’s pleas, saying that he has chosen Glauce. Medea, hurt and enraged, curses Giasone, calling on the gods of Olympus to help her take revenge.

第一幕
古科林斯。科林斯公主格勞斯在自己大婚前一天，在克萊昂特宮殿外為自己和英雄伊阿宋的婚禮作準備。這天她本該滿心歡喜，但實際上她的內心卻被憂慮充斥：伊阿宋與魔女美狄亞糾纏多年，美狄亞還為他生下了孩子。格勞斯知道，美狄亞和伊阿宋有著剪不斷理還亂的過往——魔女美狄亞用自己的法術幫助伊阿宋盜取了寶物金羊毛，為了助他奪回王位，她還殺死了自己的弟弟和伊阿宋的叔叔，最終與伊阿宋一同被流放到科林斯。格勞斯對這段過往心知肚明，她擔心美狄亞對伊阿宋餘情未了，會出手阻撓婚禮。伊阿宋對格勞斯發誓說自己對美狄亞已沒有任何舊情，然後便開始準備婚禮。然而慶典還是因為美狄亞的出現而中斷了。她要伊阿宋回到自己身邊。伊阿宋拒絕了她的請求，表示自己已經選擇了格勞斯。美狄亞悲憤交加，她詛咒伊阿宋，並請求奧林匹斯山眾神幫助自己復仇。

Act II
Inside the palace, Medea is still burning with fury over Giasone’s betrayal. Concerned by Medea’s obvious distress, Neris suggests that she leave Corinth. King Creonte arrives, and he, too, asks Medea to leave the city. Medea pleads with Creonte to be allowed just one more day with her children. When Creonte agrees, she seems to calm down, and she even orders Neris to deliver a gown and crown as presents to the bride-to-be. As the wedding procession passes by, however, Medea expresses cruel wishes for the newlyweds.

第二幕 
宮殿內，美狄亞依然因伊阿宋的背叛而怒火中燒。妮莉絲見美狄亞痛苦萬分，便建議她離開科林斯。國王克萊昂特來了，他也要求美狄亞離開。美狄亞懇求克萊昂特讓自己和孩子們再多待一天。克萊昂特答應後，她看似平靜了下來，還讓妮莉絲送給准新娘一件禮袍和一頂頭冠作為禮物。然而，婚禮進行之時，美狄亞向這對新人下了惡毒的詛咒。


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Act III
Between the palace and the temple, Medea greets her two children as a dark storm appears in the sky. Suddenly, cries of lamentation issue from the palace: Medea’s presents were soaked in poison, and Glauce has died as a result. As an outraged crowd assembles, Medea, her children, and Neris escape and hide in a nearby temple. When Medea and Neris finally emerge from the temple, the sorceress is holding a bloody knife. Thinking only of hurting Giasone as much as possible, she has murdered her own sons. Giasone, realizing what has happened, collapses in grief. Medea delivers a final curse and sets the temple on fire. Thunder roars and lightning flashes through the sky as the terrified crowd flees the blazing temple.

第三幕
美狄亞在宮殿和神廟之間見到了自己的兩個孩子，這時天空中出現了烏雲。宮殿內突然傳來悲聲：原來美狄亞的禮物都是用毒藥浸染過的，格勞斯因此毒發身亡。憤怒的人群聚攏了過來，美狄亞、她的孩子以及妮莉絲逃了出去，躲進了附近的神廟。當美狄亞和妮莉絲再度現身的時候，這位魔女手握著一把帶血的刀。為了給伊阿宋造成最大的打擊，她親手殺死了自己的兩個兒子。伊阿宋終於反應過來到底發生了什麼，他悲痛萬分，徹底崩潰了。美狄亞拋下最後一句詛咒，將神廟付之一炬。電閃雷鳴之間，恐慌的人群從熊熊燃燒的神廟中爭相逃離。