Oberon, in a cruel attempt to punish Titania for defying him and to distract her so she will give up the changeling, gets Puck (a trickster fairy or hobgoblin also known as Robin Goodfellow) to use a magic love-juice on her that makes the sleeper fall in love with the first being he or she sees on waking.
On hearing Demetrius reject Helena’s advances, Oberon describes the pair to Puck and tells him to use the love-juice on Demetrius as well.
Oberon returns Bottom to his original form and releases Titania from her enchantment.
The lovers return to Athens for a triple wedding, at which the workers perform their play, ‘Pyramus and Thisbe’.
Egeus demands the privilege of Athens: that if Hermia refuses to marry his choice, he has the right either to force her to marry or to have her killed.
Theseus gives Hermia four days to choose either to obey her father, die or become a nun.
He terrorises them, transforming Bottom the Weaver into a man with the head of an ass.
The others flee in terror, while Bottom, unaware of his transformation, remains in the wood.
Oberon, having watched the fallout of the scheme, decides to restore order.
Puck herds the lovers until they all sleep, keeping Lysander and Demetrius apart so they don’t fight, and re-dosing Lysander so that he’ll fall back in love with Hermia on waking.