Theseus, duke of Athens, after conquering the warrior Amazons in battle, is in turn conquered by the charms of their queen, Hippolyta, and they plan to marry. Their preparations are interrupted by Egeus, who brings his daughter, Hermia. Egeus commands Hermia to wed Demetrius. Hermia pleads to be allowed to marry the other suitor, the one she loves—Lysander. The duke orders her to obey her father under penalty of death or confinement in a convent. Hermia and Lysander bewail the harsh decree and secretly agree to meet in a wood and elope. They tell their plans to Helena, a jilted sweetheart of Demetrius, and she, to win back his love, goes straightway to inform him of the plan. Meanwhile, a group of rough Athenian tradesmen plan to perform a play for Theseus's wedding.
In the forest, the fairy king and queen, Oberon and Titania are arguing. Oberon bids Puck procure a love-juice to pour upon Titania's eyelids when she is asleep, in order that she may love the first thing her waking eyes behold. Just then, Oberon sees Demetrius reject Helena and tells Puck to anoint Demetrius's eyes also, so that he will fall in love with Helena. Lysander and Hermia arrive, and Puck in error anoints Lysander's instead of Demetrius's eyes, so that Lysander, happening to awake just as the neglected Helena wanders by, falls in love with her—and abandons Hermia.
The same enchanted spot in the forest happens to be the place selected by Bottom and company for the final rehearsal of the play they are planning to perform at Theseus's wedding. Puck passes that way while they are rehearsing, and mischievously and magically crowns Bottom with an ass's head. Titania awakens and falls in love with Bottom.
Oberon finds that Puck has anointed the eyes of Lysander instead of those of Demetrius, so Oberon anoints Demetrius's eyes with the love potion. When Demetrius awakes, he sees his neglected Helena being wooed by Lysander. His own love for her returns, and he is ready to fight Lysander. Puck repairs the blunder by anointing Lysander's eyes, in order to dispel the illusion caused by the love-juice. All will be in order; Lysander will love Hermia, and Demetrius will love Helena. Titania woos Bottom until Oberon, whose anger has abated, removes the spell from her eyes. Bottom is restored to his natural form, and he rejoins his comrades in Athens.
Theseus and Hippolyta, on an early morning hunting trip in the forest, discover the four lovers. The duke relents and bestows Helena upon Demetrius and Hermia upon Lysander. Bottom's players come to Theseus's wedding and present the "comic" tragedy of Pyramus and Thisbe, which is performed in wondrous and hilarious fashion. After the company retires for the night, Puck returns and blesses the three wedded pairs.