Armide, a warrior princess and sorceress, is praised by her confidantes Phénice and Sidonie for her victory over the Crusaders whom she has taken captive. However, Armide expresses her anger and frustration because she has not been able to prevail over Renaud, the most valiant of the Christian knights. Armide’s uncle, Hidraot, urges his niece to choose a husband, but she declares that were she to yield to love she would only consider someone who could conquer Renaud. Amidst the celebration of Armide’s victory, Aronte, who was guarding the prisoners, enters mortally wounded, announcing the prisoners’ rescue by Renaud. Armide and Hidroat swear that such an enemy will not escape their vengeance.
Artémidore, one of the knights rescued by Renaud, praises his rescuer and asks him to flee the place where Armide rules. Renaud assures Artémidore that his heart is safe from Armide’s enchantment. Hidraot and Armide conjure up demons to put Renaud to sleep. The hero admires his surroundings and sits down to rest. Armide enters, intending to kill Renaud as he sleeps. Instead, she is overcome by love for him, and decides that her triumph, thanks to her spells, would be to bring Renaud into her power and have him love her. She asks the demons to transform themselves into zephyrs to carry her and Renaud far away.
Armide deplores the conquest of her heart by Renaud. Phénice and Sidonie urge Armide to abandon herself to love, but Armide is troubled because, while she is in love with him, he is bound to her only by her spells. Armide invokes the spirit of Hate to rescue her from her love for Renaud. Hate and her followers perform a powerful invocation, but Armide cannot give up Renaud, and she sends Hate away. Hate curses Armide, condemning her to the punishment of endless love.
Two of Renaud’s companions, Ubalde and the Danish Knight, are searching for their hero to rescue him from Armide. They manage to resist the temptations and dangerous delights set in their path by Armide.
Armide and Renaud declare their passion but Armide is haunted by a dark foreboding, and wishes to consult the Underworld. She retires and leaves the Pleasures and a troop of Fortunate Lovers to amuse Renaud. In her absence, Ubalde and the Danish Knight discover Renaud and break Armide’s spell. She returns in time to confront Renaud as he leaves, imploring him to take her with him as a captive if he will not remain as her lover. For Renaud, Duty and Glory demand that he leave her, but he pities her fate. Armide, left alone, laments her love and the horror of her torment, and declares that the hope of vengence is all that remains to her. Armide then bids the demons destroy her enchanted palace, hoping to bury forever her cursed love.