ACT I
Golaud, a widower and grandson of King Arkel, has lost his way in a dense forest and fears he will never find his way out. There he discovers a woman in tears by a spring. She has escaped from a terrible ordeal and is also lost in the forest. She tells him her name is Mélisande. She threatens to kill herself if Golaud attempts to retrieve a crown, which has fallen in the water. Even though she evades his questions, he persuades her to come with him.
Golaud explains these events in a letter to his half-brother Pelléas that their mother Geneviève reads to King Arkel. He has now married Mélisande, despite knowing no more about her than on the day they met. He wants to bring her back to the castle if Arkel will give them his blessing. Arkel acknowledges that it was not his plan that Golaud should marry someone unknown, but will not oppose Golaud’s choice. Pelléas asks Arkel’s permission to visit a friend who is dying; Arkel says that while Pelléas’ own father is dying in the castle, he must stay.
Geneviève is showing Mélisande the castle’s gardens and the view to the sea beyond. They both remark on the darkness of the castle and the forest around it. They are joined by Pelléas. They watch the ship that brought Mélisande and Golaud to the castle sail away.
ACT II
Pelléas has brought Mélisande to a well in the grounds of the castle. She plays with her wedding ring and as the clock strikes midday, she drops it irretrievably into the water.
Golaud has been thrown from his horse on the stroke of midday. Mélisande tries to tend to him. She is unhappy and wants to leave the castle. Golaud acknowledges that the castle is very gloomy but reassures her that she will get used to it. He notices Mélisande is not wearing her wedding ring and becomes angry. When Mélisande tells him she must have dropped it in a cave by the sea, he tells her to go with Pelléas and find it immediately, even though it is already dark.
Pelléas and Mélisande go to the sea cave where she has told her husband she dropped the ring. By the light of the moon, they see three starved old people who are leaning against each other as they sleep, take fright and leave.
ACT III
Pelléas arrives below Mélisande’s window and marvels at her beauty. He reaches for her hair and it gets tangled in a willow tree. Golaud arrives and chides them for playing together.
Golaud takes Pelléas down into the castle’s underground vaults and forces him to lean out over a chasm whose water emits a stench of death.
They emerge and Pelléas is ecstatic to be in fresh air and light. Golaud warns him to stay away from Mélisande, especially as she may now be expecting a child.
Golaud interrogates his young son Yniold, who has been spending a lot of time with Pelléas and Mélisande, about what they do when he is not there. His innocent answers merely fan Golaud’s jealousy. As they are underneath his wife’s window, Golaud makes Yniold spy on the couple in her room: they are not speaking, they are looking at the light and they don’t shut their eyes at all…
ACT IV
Pelléas’ father has recovered and the castle has come to life. Pelléas can now finally leave the kingdom and asks Mélisande to meet him one final time before he goes away forever. They arrange to meet at the well.
Arkel has been observing Mélisande since she arrived and pitying her. He predicts that her youth and beauty will usher in a new era for the castle. Golaud enters in a jealous rage and angrily confronts Mélisande, disparaging her innocence and abusing her in front of Arkel.
Yniold is trying to retrieve his golden ball, but it is stuck under an immovable rock. He sees a flock of sheep. They are frightened and even though night is falling the shepherd is not leading them back to the fold. Then where are they going…?
Pelléas and Mélisande meet at the well and finally declare their love for each other. The castle gates close on them and in the realisation that it is too late for them to return, they embrace ecstatically. Golaud is watching them from the shadows. He strikes Pelléas dead and pursues Mélisande through the woods in silence.
ACT V
Mélisande has given birth to a daughter and is asleep. A remorseful Golaud fears his wife is dying and that he is responsible, though the doctor says this is impossible.
When Mélisande briefly awakens, Golaud once again questions her about the nature of her relationship with Pelléas, but gets no satisfaction from her replies. The castle servants enter the room to acknowledge Mélisande’s passing. She quietly dies and Golaud is left alone.
