The opera opens in the forest, where Gurnemanz, an old servant of Amfortas, guardian of the Holy Grail, is lying asleep with two squires.  Suddenly, reveille sounds from the top of Mount Salvat, the sacred hill upon which the temple stands.  Gurnemanz, springing to his feet, rouses the squires, and bids them prepare the bath for their ailing master, who will soon appear as is his daily custom.

This Amfortas, whose coming they momentarily expect, is the son of Titurel, the founder of the temple erected on Mount Salvat for the reception of the Holy Grail, a vessel in which Joseph of Arimathea caught a few drops of blood from the dying Redeemer’s side, after it had served as chalice during the Last Supper.  Titurel, feeling too old to continue his office as guardian of the Grail, appointed Amfortas as his successor, giving him the sacred lance which pierced the Saviour’s side, and told him that none could resist him as long as he wielded it and kept himself perfectly pure.

During many years Amfortas led a stainless life, defending the Holy Grail from every foe, performing all his sacred offices with exemplary piety, and teaching the Knights of the Grail to fight for the right, and rescue the feeble and oppressed.  He also sent out messengers to all parts of the world to right the wrong, whenever called upon to do so, by the words which suddenly appeared and glowed like fire around the edge of the mystic vase.  All the knights who served the Holy Grail were not only fed with celestial viands by its power alone, but were endowed with resistless might, which assured their victory everywhere as long as they remained unknown.  They had moreover the privilege of recovering, as if by magic, from every wound.  Of course, many knights were desirous of being admitted into the temple, but none except those whose lives were pure and whose purposes lofty were ever accepted.  When Klingsor, the magician, attempted to enter, therefore, he was repulsed.  In his anger he established himself upon the other side of the mountain, where, summoning all the arts of magic to his aid, he called up delusions of every kind.  Thus he beguiled many of the knights in search of the Holy Grail, caught them in his toils and led them on to sin, until they were unfit for the holy life to which they had once aspired.

Amfortas, hearing of this, and too confident in his own strength, sallied forth one day, armed with the sacred lance, determined to destroy Klingsor, and put an end to his magic.  But alas! he had no sooner entered the magician’s garden, where roamed a host of lovely maidens trained to lure all men to sin, than he yielded to the blandishments of the fairest among them.  Carelessly flinging his sacred lance aside, he gave himself up to the delights of passion.  Such was his bewitched condition that he never even noticed the stealthy approach of the magician, who seized the lance and thrust it into his side.  This deep wound, which had refused to heal ever since, caused him incessant tortures, which were increased rather than diminished whenever he uncovered the Holy Grail.