Puck is ordered by King Oberon to put the love juice into Demetrius' eyes
Puck got Demetrius and Lysander mixed up and put the love juice into Lysanders eyes
What hast thou done? Thou hast mistaken quite, And laid the love-juice on some true love's sight
Puck fixes his mistake by putting the love juice into Demetrius' eyes
Demetrius and Lysander both now love Helena. Only one of them can have her so they want to settle in a dual
Puck uses the men's voices to chase them to different sides of the forest where Demetrius met with Helena and Lysander met with Hermia and they slept. Puck put the love juice into the men's eyes.
The couples wake up to to Egeus Hippolyta and Theseus standing by them. Egeus demands that Hermia is not with Lysander. But Theseus overtakes him. The couples get married that night at Theseus and Hippolyta's wedding