From time to time Kurvenal interrupts his sad watch beside the pallid sleeper to call to a shepherd piping on the hillside, and to inquire of him whether he descries any signs of the coming sail.  Slowly and feebly Tristan at last opens his eyes, gazes dreamily at his attendant and surroundings, and wonderingly inquires how he came thither.  Kurvenal gently tells him that he bore him away from Cornwall while wounded and unconscious, and brought him home to recover his health amid the peaceful scenes of his happy youth; but Tristan sadly declares that life has lost all its charms since he has parted from Ysolde.  In a sudden return of delirium the wounded hero then fancies he is again in the forest, watching for the light to go out, until Kurvenal tells him that Ysolde will soon be here, as he has sent a ship to Cornwall to bring her safely over the seas.

These tidings fill Tristan’s heart with such rapture that he embraces Kurvenal, thanking him brokenly for his lifelong devotion, and bidding him climb up into the watch-tower that he may catch the first glimpse of the coming sail.  While Kurvenal is hesitating whether he shall obey this order and leave his helpless patient alone, the shepherd joyfully announces the appearance of the ship.  Kurvenal, ascending the tower, reports to his master how it rounds the point, steers past the dangerous rocks, touches the shore, and permits Ysolde to land.

Tristan has feverishly listened to all these reports, and bids Kurvenal hasten down to bring Ysolde to him; then, left alone, he bursts forth into rapturous praise of the happy day which brings his beloved to him once more, and of the deep love which has called him back from the gates of the tomb.  His impatience to see Ysolde soon gets the better of his weakness, however, and he struggles to rise from his couch, although the exertion causes his wounds to bleed afresh.  Painfully he staggers half across the stage to meet Ysolde, who appears only in time to hear his last passionate utterance of her beloved name, and to catch his dying form in her arms.  She does not realise that he has breathed his last, however, and gently tries to woo him back to life, and make him open his eyes.  But when all her efforts have failed, and she finds his heart no longer beats beneath her hand, she reproaches him tenderly for leaving her thus alone, and sinks unconscious upon his breast.  Kurvenal, standing beside the lovers, speechless with grief, is roused to sudden action by the shepherd’s hurried announcement that a second ship has arrived, and that King Mark, Melot, and all his train, are about to appear.  Frenzied with grief, and thinking that they have come once more to injure his master, Kurvenal seizes his sword, and, springing to the gate, fights desperately until he has slain Melot, and falls mortally wounded at Tristan’s feet.