Fairies sing around the sleeping Oberon in his bower. Puck enters and recounts Oberon's quarrel with Titania, his queen, where Oberon vowed not to be reconciled with her until a pair of human lovers are found who have been faithful to each other through all perils and temptations. Puck has ventured everywhere to find such couples, but in vain. Awakening, Oberon curses the rash vow he made. Puck tells him that the knight Sir Huon has been ordered by Emperor Charlemagne to go to Baghdad, slay the man on the Caliph's right hand, then kiss and wed the Caliph's daughter. Oberon decides that this knight and the princess will be the ones to assist him in his reconciliation with his queen. A vision of Reiza is conjured for Huon and his squire Sherasmin, and they are given a magic horn to summon aid from Oberon if needed. Fairies are called in to carry Huon on his mission.
On the banks of the Tigris Prince Babekan is rescued from a lion by Huon and Sherasmin. Babekan is actually the betrothed of Reiza but when he attacks Huon and Sherasmin they put the prince and his band to flight. Next, Namouna, an old woman tells Huon that Reiza is to be married the next day, but has also had a vision which has drawn her to Huon.
In the palace of Haroun al Rachid Reiza confides to her attendant that she will only marry the knight in her vision, and, as Fatima announces the arrival of Huon the two women rejoice in anticipation.
In the splendid court of Haroun al Rachid a chorus sing praises to their ruler. Reiza is led in to wed Prince Babekan, seated on the caliph's right, but Huon and Sherasmin burst in, kill Babekan and flee with the princess and Fatima. A ship is to take them to Greece. The two couples express their love as they depart.
Puck invokes the spirits of the elements to wreck Huon's ship. Huon and Reiza survive and he goes in search of more survivors while she sings of the fury and menace of the sea. At the close of her aria she espies a ship approaching and signals to it. But it is a pirate ship and Abdallah and his crew abduct Reiza. Huon tries to save her but is wounded; he manages to sound the magic horn and Oberon appears. Oberon tells Puck to take Huon to Tunis and the house of Ibrahim. The mermaids sing happily over the unconscious prince.
In the garden of the Emir's house in Tunis Fatima sings of her fate as a slave. She and Sherasmin are now married and they sing of their childhood. Puck makes Huon appear, and after Fatima tells him that Reiza is in a harem, they plan her rescue.
In the harem of Almanzor, Reiza laments her lot and manages to get a message to Huon who sets off to release her. However, by accident he encounters Roshana, the Emir's wife, who tries to persuade Huon to kill Almanzor and marry her. He refuses but the Emir discovers them and condemns Huon to death at the stake. Reiza implores the Emir to pardon Huon, but as she had scorned his advances, the Emir refuses and orders the two to be burned together. Oberon is summoned by Sherasmin blowing the magic horn. The Emir's slaves begin to dance, and after a second blast on the horn, Oberon and Titania appear. The Tunisians flee, the lovers are transported to Charlemagne's court, and Huon is pardoned.