Act I
In the Pyrenees, the old Knight Titurel lives in the Castle of Montsalvat where the Grail is held. His son, Amfortas, had been injured by the magician Klingsor, enemy of the Knights of the Grail, by his own Holy Spear, the arm that injured the Christ. Amfortas can only be healed by the contact with this Spear.
In the forest, around the castle, the Knight Gurnemanz and his two knaves meet Kundry, messenger of the knights of the Grail to whom Klingsor cast an evil spell. She brings a balsam from Arabia to cure the king. He accepts but it has been said that only 'an innocent with a pure heart' would be able to get the Lance back and cure him.
A young man, guilty of having killed one of the sacred swans of Montsalvat, is brought in by a troop of warriors. It’s Parsifal, a young wandering knight, who seems to know nothing about his origins.
Act II
At the Castle of Klingsor, the latter asks Kundry to entice Parsifal to make him sin, so that he can retrieve the Holy Grail. Klingsor then transforms his castle into a beautiful garden where young girls in bloom use their charm to seduce Parsifal, in vain. Only Kundry is able to do so.
As he realises that he has sinned, Parsifal composes himself and cries out his pain. Upset, Kundry understands she has to break Klingsor’s enchantment and look for redemption in Parsifal’s love. But Kundry is rejected by him, so she decides to call Klingsor who cast the Holy Spear. Parsifal seizes it, makes the sign of the cross: Klingsor and his castle get destroyed and Kundry faints.
Act III
Gurnemanz lives as a hermit not far from the mountain of Grail. Kundry visits him, asking him to serve again the Knights of the Grail when suddenly, a black-armored knight arrives: it’s Parsifal. Gurnemanz understands he is the 'innocent with a pure heart' and crown him king of Grail and baptizes Kundry. Back to the castle of Grail, Parsifal heals Amfortas by touching him with the Holy Spear. Eventually forgiven, Kundry dies.