Though there are four different plots in "A Midsummer Night's Dream," there is one theme that connects them all: love.
The wedding of Theseus and Hippolyta: Theseus is the ruler of Athens and has "won" Hippolyta during a battle. At the beginning of this play, they are preparing for their wedding. The couple appears in act 1 and then disappears for the duration of the play, reappearing in act 4.
The fiasco of the young lovers Lysander, Hermia, Demetrius, and Helena: Hermia is in love with Lysander even though her father wants her to marry Demetrius. Demetrius is in love with Hermia but eventually falls in love with Helena thanks to the work of the fairies. Lysander loves Hermia, but he falls in love with Helena due to love potion after the fairies mistake him for Demetrius. At the beginning of the play, Helena loves Demetrius; those feelings are not returned until the fairies intervene. These constantly shifting alliances provide much room for comedy as the characters often find themselves confused in their attempts at love.
The interventions of the "rude mechanicals": The mechanicals, or artisans, are the six characters who perform the play that is meant to mark the upcoming wedding of Theseus and Hippolyta. This group includes Snug, Quince, Starveling, Flute, Snout, and Bottom.
The conflict between fairies, including Oberon, Titania, and Puck: Titania and Oberon have an ongoing dispute over what to do with a new Indian child. Oberon wants make him a servant, but Titania wants to care for the young child. Oberon enlists the help of Puck to make Titania fall in love with Bottom, whom Puck has recently transformed into a man with the head of an ass. Oberon and Titania eventually reconcile, however.