Theseus, the Duke of Athens, is preparing for his marriage to Hippolyta, Queen of the Amazons, A courtier seeks the Duke's help because his daughter, Hermia, will not agree to his choice of Demetrius as a husband: she’s in love with Lysander. The Duke tells Hermia to obey her father, or either die or accept a life as a nun. Lysander and Hermia plan to run away to get married, and they tell Helena, who is in love with Demetrius, but he hates her and loves Hermia. The lovers run away from Athens but get lost in the woods. They are followed by Demetrius, and then by Helena, who has told him of their intentions.
Oberon, king of the fairies, who lives in the woods, has quarrelled with his queen, Titania, over an Indian boy she refuses to give him. Oberon overhears Helena and Demetrius arguing and sends his mischievous servant, Puck, to get a flower whose juice has the power to make people fall in love with the first creature they see when the juice is placed on their eyelids while asleep. He instructs Puck to put some drops on Demetrius’ eyes. Mistaking the Athenian he seeks, Puck puts the flower juice on the eyes of the sleeping Lysander so that when he is woken by Helena he immediately falls in love with her and rejects Hermia.
Some artisans (skilled workers) are rehearsing a play about the tragic love-story of Pyramus and Thisbe to present before Theseus on his wedding day. Bottom, the weaver, is to play the lover, Pyramus, while Flute, the bellows-mender, is to play Thisbe. The others play the parts of the Moon, the Wall and the Lion and they are directed by Quince, the carpenter. Puck overhears their rehearsals in the wood and he plays a trick on them by giving Bottom an ass's head which frightens the others away. Bottom is lured towards the sleeping Titania whom Oberon has treated with the flower juice. On waking, she falls in love with the ass and entertains him with her fairies, but when Bottom falls asleep beside her, Oberon restores Titania’s sight and wakes her. She is horrified at the sight of what she has been in love with and is reunited with Oberon.
Puck removes the ass’s head and Bottom returns to Athens and rejoins his friends as they prepare to perform their play. Meanwhile the lovers' arguments tire them out as they chase one another through the woods and when Demetrius rests, Oberon puts magic juice on his eyes so that both he and Lysander chase Helena until the four lovers fall asleep, exhausted. Puck puts juice on Lysander's eyes before the lovers are woken by Theseus and Hippolyta and their dawn hunting party. Happily reunited to each other, Lysander with Hermia, Demetrius with Helena, they agree to share the Duke's wedding day. The workers perform the play of Pyramus and Thisbe before the wedding guests. As the three couples retire Puck and the fairies return to bless the palace and its people.