ACT I
France and Spain, c. 1560. Against the wishes of the Spanish King Philippe II, his son and heir, Don Carlos, has traveled incognito to Fontainebleau, where negotiations are underway for a peace treaty between Spain and France. He has seen his intended bride, Élisabeth, daughter of the French king, and fallen in love with her on sight. When he meets Élisabeth and her page, who have been hunting and become lost in the forest, Carlos offers his protection without revealing his identity. Élisabeth questions him about her future husband, apprehensive over her marriage to a stranger. Carlos gives her a miniature portrait of himself, and she realizes that he is the prince. It is clear to them both that their feelings of love are mutual. Their happiness ends, however, when news arrives that the treaty arrangements have been altered, and Élisabeth is instead to marry King Philippe, Carlos’s father. Élisabeth reluctantly accepts. While all around them celebrate the end of the war, Élisabeth and Carlos are devastated.

第一幕
1560年，法國和西班牙。身位王位繼承人的唐．卡洛違抗父親西班牙國王菲臘二世的意旨，微服到訪楓丹白露，西班牙與法國正在當地商討和約。他已見過他的未來新娘──法國國王的女兒伊莉莎白，並對她一見鍾情。當他在森林遇見正在打獵但迷了路的伊莉莎白及其侍從，他主動提出要保護她們，但沒有透露自己的身分。伊莉莎白向他詢問關於自己未來夫婿的事，憂心自己將要嫁給一個陌生人。卡洛將自己一幅細小的畫像送給伊莉莎白，於是她發現原來眼前人就是自己未來的丈夫。兩個人都清楚知道彼此的愛意。然而，兩人的幸福時光隨著兩國更改和約內容而告終，伊莉莎白要下嫁的不再是卡洛，而是卡洛的父親西班牙國王菲臘。伊莉莎白只能無奈接受。正當周圍的人都慶祝兩國間的戰爭完結，伊莉莎白和卡洛則悲痛欲絕。


ACT II
Carlos seeks peace at the monastery of St. Just in Spain, where he prays at the tomb of his grandfather, Emperor Charles V. A monk, who seems to be the emperor’s ghost, confronts him. His friend Rodrigue, the Marquis of Posa, arrives to remind Carlos of his commitment to the cause of the Flemish people, who are oppressed by Spanish rule. When Philippe and Élisabeth arrive, Carlos confesses to Posa his love for the queen, and the two men pledge themselves to the cause of liberty and swear eternal friendship.In a garden outside the monastery, Princess Eboli entertains the other ladies of the court with a song. Élisabeth enters, followed by Posa, who hands her a secret letter from Carlos asking for a meeting. When he is admitted, Carlos asks the queen to obtain Philippe’s permission for him to go to Flanders, then suddenly declares his continuing love. Élisabeth rejects him, and Carlos rushes off. The king enters and, finding the queen alone, banishes the Countess of Aremberg, who should have been attending her. Left alone with the king, Posa challenges Philippe to end his oppression of the Flemish people. Philippe refuses but is impressed by Posa’s courage. He warns him to beware of the Inquisition and tells Posa that he suspects his wife and Carlos, asking Posa to watch them. Posa accepts the assignment, knowing that being in the king’s confidence will be valuable.

第二幕
卡洛在位於西班牙聖烏斯特的修道院避靜，並在他已故的祖父國王查理五世的墳前禱告。一名看似查理五世鬼魂的僧侶責難他。卡洛的友人羅德里格（波薩侯爵）到訪，提醒卡洛作為子，要銘記對飽受西班牙統治者欺壓的佛蘭芒人作出的承諾。當菲臘與伊莉莎白到來後，卡洛向波薩透露自己對王后的愛意，兩人誓言要投身爭取自由，並且發誓友誼永固。修道院的庭園外，公主艾伯莉為其他王室名媛高歌一曲。伊莉莎白步入庭園，波薩緊隨其後，親手交給她一封卡洛的密函，信中卡洛要求與她見面。卡洛獲召入宮後，要求王后使國王菲臘批准他前往法蘭德斯，然後突然向她表示仍然深愛著她。伊莉莎白拒絕了他，卡洛匆匆離去。國王回宮後發現只有王后一人，於是將本應侍奉王后左右的阿倫貝格公爵夫人驅逐出宮。波薩趁與國王菲臘獨處時，要求菲臘停止壓迫佛蘭芒人。菲臘斷然拒絕，但非常佩服波薩的勇氣。他告誡波薩要提防宗教裁判所，並向他透露自己懷疑妻子和卡洛有私情，要求波薩監視他們。波薩深知取得國王的信任將會帶來莫大好處，於是接受了任務。


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ACT III
In the queen’s gardens in Madrid, Élisabeth, tired of the festivities, exchanges clothes with Eboli so that she can take her place. Eboli, suspecting that Carlos loves her, writes an unsigned message to him to arrange a secret meeting. Carlos arrives and, fooled by her attire and thinking that Eboli is Élisabeth, again declares his love. When he discovers her identity, he recoils and rejects her advances. From this, Eboli discovers Carlos’s treasonous love for Élisabeth and swears to expose him. Posa arrives in time to overhear Eboli and threatens to kill her, but Carlos prevents him. Eboli leaves in fury. Posa explains that Carlos is now in imminent danger and urges him to hand over any incriminating documents so they won’t be found by Philippe’s men.At a public burning of heretics in front of Madrid’s Basilica of Our Lady of Atocha, Carlos leads a group of Flemish deputies to Philippe. The king rejects their pleas for freedom. When he also dismisses Carlos’s own request to rule Flanders, the prince draws his sword on his father. Posa disarms him, and Carlos is arrested. In thanks, Philippe makes Posa a duke. As a group of heretics is led to the stake, a celestial voice welcomes their souls into heaven.

第三幕
在位於馬德里的王后花園中，厭倦了慶祝活動的伊莉莎白與艾伯莉交換衣服，以便艾伯莉可以暫時頂替自己。艾伯莉懷疑卡洛愛上自己，給卡洛寫了一封沒有下款的信，要求與他私下會面。卡洛應約赴會，被她的服飾所騙，誤以為她就是伊莉莎白，於是他再次向她示愛。當他發現對方的真正身分，旋即後退幾步並且著她不要走近。由此，艾伯莉得悉卡洛對伊莉莎白的非分之想，並且揚言要揭穿他。波薩及時到達，偷聽到艾伯莉的說話，並威脅要殺死她，不過卡洛阻止了他。艾伯莉憤然離開。波薩向卡洛解釋他現在身陷險境，催促他儘快交出任何足以指證他的文件，以免被菲臘的手下找到。馬德里的阿托查聖母聖殿前方，正在公開舉行火燒異教徒的儀式，卡洛帶領一班佛蘭芒人代表覲見國王菲臘。國王拒絕了他們渴求自由的請求。當國王也駁回了由卡洛自己統治法蘭德斯的請求後，王子卡洛隨即拔劍指向自己的父皇。波薩迫使卡洛解除武裝，卡洛淪為階下囚。國王為了答謝波薩，賜予他公爵銜頭。當一群異教徒被帶到火刑柱時，一把天籟之聲引領他們的靈魂升上天堂。


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ACT IV
In his study at night, the king reflects on his life with a wife who doesn’t love him. He consults with the old, blind Grand Inquisitor, who consents to the death sentence for Carlos: As God sacrificed his son to save mankind, so Philippe must put aside his love for his son for the sake of both church and state. The Inquisitor also demands that Posa be handed over to him, but Philippe refuses. As he leaves, Philippe wonders if the throne must always yield to the altar. Élisabeth enters, having discovered that her jewel case has been stolen. Eboli, who knows that Élisabeth keeps a portrait of Carlos in it, has denounced her and given the box to the king as evidence. Philippe now shows the box to Élisabeth, takes out the portrait, and accuses her of adultery. Élisabeth collapses, and the king calls for help. Eboli and Posa rush in. Posa expresses amazement that a king who rules half the world cannot govern his own emotions, while Eboli feels remorse at what her jealousy has brought about. Alone with Élisabeth, Eboli confesses that she not only falsely accused her but that she has been the king’s mistress. Élisabeth orders her exile from the court. Eboli laments her fatal beauty and swears to spend her final day in Spain trying to save Carlos.

Posa visits Carlos in prison to tell him that he has used the secret papers to take upon himself the blame for the Flemish rebellion and will die in Carlos’s place. Agents of the Inquisition arrive unseen and shoot Posa. As he dies, he exhorts Carlos to take up the cause of liberty for Flanders and tells him that Élisabeth will meet him at the monastery of St. Just. He declares that he is happy to have sacrificed his life for a man who will become Spain’s savior.

第四幕
一個晚上，國王菲臘在書房回想自己有一個不愛自己的妻子的生活。他諮詢了年邁失明的宗教大法官如何處置卡洛，宗教大法官同意判處卡洛死刑：如同上帝為人類犧牲了自己的兒子，菲臘必須為了教會和國家放下自己對兒子的愛。大法官還要求將波薩交給他發落，但是菲臘拒絕了他的要求。大法官離開後，菲臘仍在沉思王室是否總是要屈服於教會。伊莉莎白步入書房，發現她的首飾箱被盗。艾伯莉知道伊莉莎白在箱中保存了卡洛的畫像，斥責了伊莉莎白所為，並且將首飾箱交給了菲臘作為證據。菲臘在伊莉莎白面前出示首飾箱，拿出卡洛的畫像，指控她通姦。伊莉莎白崩潰倒地，菲臘見狀召援求救。艾伯莉和波薩衝入書房。波薩驚訝於統治世界一半領土的國王控制不了自己的情緒；而艾伯莉對自己的妒忌心所帶來的後果感到懊悔。趁著與伊莉莎白獨處的時候，艾伯莉承認她不僅誣衊伊莉莎白，而且自己一直是國王菲臘的情婦。伊莉莎白命令將她逐出王宮。艾伯莉感慨自己是禍水紅顏，發誓救出卡洛。

波薩探望獄中的卡洛，告訢卡洛他已經利用了秘密文書，將所有關於佛蘭芒人叛亂的罪名一力承擔，代替卡洛受死。宗教裁判所的官員無聲無色地進入監獄並且槍擊了波薩。波薩死前，力勸卡洛負起為法蘭德斯爭取自由的責任，並且告訴他伊莉莎白將在聖烏斯特的修道院與他相見。波薩表示他樂於為將會拯救西班牙的人犧牲性命。


ACT V
Élisabeth has come to the monastery, wanting only her own death. When Carlos appears, she encourages him to continue Posa’s quest for freedom in Flanders, and they hope for happiness in the next world. As they say goodbye, Philippe and the Grand Inquisitor arrive. As the agents of the Inquisition move in on Carlos, the Emperor Charles V materializes out of the darkness to insist that suffering is unavoidable and ceases only in heaven.

第五幕
伊莉莎白來到了修道院，一心只想尋死。卡洛出現後，她鼓勵卡洛延續波薩在法蘭德斯爭取自由的事業，兩人同盼來世能幸福快樂。他們道別時，菲臘與大裁判官到達。當宗教裁判所的官員走向卡洛時，國王查理五世從黑暗中現身，強調苦難常在，唯止於天國。