Theseus (the Duke of Athens) announces he will marry Hippolyta, the queen of the Amazons in four days. He hears Egeus' complaint that his daughter Hermia refuses to marry his chosen suitor, Demetrius, since she's in love with Lysander, who Egeus dislikes. Theseus declares Hermia must marry Demetrius, or choose between death or joining a nunnery. Lysander instructs Hermia to flee to the forest with him, so that they can travel to his aunt's house to marry. Hermia's friend, Helena, learns of this and decides to inform Demetrius, whom she likes (and has slept with). Demetrius, though, loves Hermia. Helena hopes they will all meet in the forest. Meanwhile, Quince, Bottom, Flute, Starveling, Snug, and Snout organize a play to be performed at Theseus' wedding.
In the forest, Oberon (the King of the Fairies) argues with Titania (the Fairy Queen) that he should have her orphan child as his page. Titania objects, asserting she is queen. They bicker that Oberon loves Hippolyta and Titania loves Theseus. To obtain the boy, Oberon orders the fairy Puck (aka Robin Goodfellow) to obtain a flower from Cupid that causes on to love the first person a person sees. Oberon plans to give it to Titania, so she'll love a vile thing and give him the child. Demetrius and Helena appear, Helena pursuing him, and he fleeing her. Puck arrives with the flower, and Oberon orders Puck to anoint Demetrius with it so he'll love Helena rather than Hermia. Oberon then anoints Titania with the flower. In the forest, Lysander and Hermia lie down to rest. Puck, thinking Lysander is Demetrius, anoints him with the flower. Helena appears and awakes Lysander, who immediately falls in love with her.
In the forest, the troupe of players discuss the logistics of their play. Puck appears and transforms Bottom to have an asses' (donkey's) head. The actors flee, but Titania awakes and falls in love with Bottom and orders her fairy servants to attend to him. Puck observes that Demetrius chases Hermia, yet she accuses him of murdering Lysander, and realises he gave the flower to the wrong man. Oberon tries to remedy this by anointing Lysander with the flower so he'll fall in love with Helena, and he does. However, now both men love Helena, while she believes both are false. Hermia arrives and Helena accuses her of conspiring with the men to tease her. Oberon, realizing Puck has caused these problems, orders him to make a thick fog to separate the four people and force them into a deep sleep, so the spell can wear off.
Oberon awakes Titania and transforms Bottom back to a human. Oberon and Titania then make up and love each other again. In the woods, Theseus, Hippolyta, and Egeus appear and awake the four. Demetrius and Lysander inform the men of their love for Helena and Hermia (respectively). The lords agree to let them marry. Separately, Bottom awakes and remembers the night's occurrences.
At dinner, they all hear Quince's ten word, tedious, brief, tragical play. In it, Thisby (played by Flute) and Pyramus (played by Bottom) whisper their love through a chink in a wall (played by Snout). They vow to meet at Ninny's tomb, but a lion (played by Snug) attacks Thisby. Pyramus arrives and finds her scarf, assumes she's dead, and kills himself. Thisby arrives to find him dead, and kills herself. After the play, at midnight, all go to bed, then the fairies appear and frolic.