2.1: Puck hangs out in the woods and bumps into one of Titania's Fairies.
2.1: Puck and the Fairy bicker about whose boss is better. Puck informs the Fairy that Titania better watch her back, because Oberon isn't happy with her.
2.1: Puck brags that he's the famous sprite with a reputation for punking hapless humans. He tells us that his boss, Oberon, loves him for being a practical jokester.
2.1: Puck hangs out with Oberon in the woods and then fetches some magic love juice for his boss. Puck is ordered to drug an "Athenian" man who's hanging out in the woods so the guy will wake up and fall in love with Helena. (He's supposed to put the juice in Demetrius's eyes.)
2.1: Puck accidentally sprinkles the love potion in Lysander's eyes instead of Demetrius's, which causes Lysander to fall out of love with Hermia and in love with Helena. Whoops. Now Demetrius and Lysander both want Helena, and Hermia is left unloved.
3.1: Puck watches the Mechanicals rehearse their play for the wedding of Theseus and Hippolyta. He can't believe his good fortune—it's not every day a sprite gets a chance to watch a bunch of bumbling craftsmen try to be serious actors.
3.1: Puck decides to pick on Bottom, one of the craftsmen. He turns Bottom's head into that of an ass. Good times.
3.1: Puck delights in all the confusion and mayhem he's caused by transforming Bottom into a strange beast. For funzies, he decides to chase the panicked craftsmen around, appearing in different frightening forms and harassing them for his own pleasure.
3.2: Puck reports to Oberon that Titania is in love with a monster and explains how it went down: When Puck came upon the Mechanicals practicing their play, he transformed Bottom's head into a donkey's. Chaos ensued and the commotion woke up Titania, who took one look at Bottom and fell in love.
3.2: Puck realizes he's drugged the wrong Athenian man when the young lovers show up and get into a big fight. He promises Oberon he'll fix the problem.
3.2: Puck enjoys watching the chaos and confusion he's caused for the young Athenian lovers. He famously declares "Lord what fools these mortals be!"
3.2: Puck swears to Oberon that he didn't mean to sprinkle the juice in the wrong guy's eyeballs. Oberon told him to find a guy "dressed like an Athenian," and that's what he did. Either way, he's not sorry it turned out this way, as the whole thing is hilarious.
3.2: Puck tells Oberon they've got to fix this business quickly, as the morning is coming and it's the hour for ghosts to wander back to their graves, which is scary and creepy.
3.2: Puck rounds up Lysander and Demetrius and watches them fall asleep. He also waits for Hermia to show up and take a nap. Then he applies the antidote to Lysander's eyes so the guy will wake up, see Hermia, and fall back in love with her.
4.1: Puck changes Bottom back to his original form.
5.1: Puck attends the weddings of Theseus and Hippolyta; Lysander and Hermia; Demetrius and Helena.
5.1: After the married couples go to bed, Puck performs his duty as a household spirit by sweeping the doorway of the house and ensuring that nothing bothers its dwellers.
Epilogue: Puck closes the play by telling the audience that, if they hate the play, they should just imagine that the whole play was a dream.