While Titania lies sleeping, Quince, Snug, Bottom, Flute, Snouth and Starveling enter the wood to practice their play. The players make decisions about how they will perform the play, how the play will be introduced. Bottom leaves as some of the lines are being read, and with him goes Puck, who has been hidden. Puck turns Bottom's head into that of a horse.
Puck jokes to himself about how Titania will find him then himself exits. As the players react to Bottom the man feels as though they are merely playing tricks on him. To show his lack of fear as the other players leave, he begins to sing a song. As he sings, he awakens the sleeping Titania, who comments on the beauty of his voice, and sends her attendants, Peaceblossom, Cobweb, Moth, and Mustardseed to attend to him, giving him ever courtesy.
Bottom introduces himself to each of them in a comical manner, and says he looks forward to getting to know them better. Titania tells her attendants to keep him quiet and bring him to her.
In another part of the wood, Oberon wonders how his plans for Titania have gone, and along comes Puck, explaining what had happened with Bottom. Oberon is overjoyed with the news and asks about the Athenians. Puck tells him all went well, but Demetrius and Hermia pass by. Oberon tells Puck, he gave the potion to the wrong man, as Demetrius was the man who needed the potion so he would fall in love with Helena. Oberon sends puck to give him the potion as soon as possible.
Meanwhile, Hermia is scolding Demetrius because she believes he killed Lysander, who suddenly disappeared in the night as far as she knows. Demetrius retorts that he did not kill Lysander, and there is no evidence of his death, and exits. Demetrius finds a soft place to sleep and lies down.
Puck returns to Oberon, telling him the job is complete.
As Demetrius awakens he finds Lysander and Helena, Lysander still proclaiming his love to her, and Helena denying it whole hearted. Demetrius joins Lysander in doting upon Helena who now believes they are both just playing a horrible trick on her. Hermia then finds all of them and asks why Lysander left her.
Lysander replies that he hates Hermia, and loves Helena. Hermia seems disheartened, then Helena berates Hermia for sending them men who love her to make fun of her with praise. The two men become enraged at one another, trying to prove their love of Helena through various vows until they begin to insult one another until they decide to fight.
Lysander tells Hermia to leave, that he hates her. Hermia then accuses Helena of stealing Lysander's love, Helena retorts that they are all playing a joke on her. Hermia becomes so enraged at Helena's perceived theft of Lysander that she threatens to tear Helena's eyes out. Helena explains her love toward Hermia, and tells her that she told Demetrius about the wood because of her love for him, and followed also out of love. Helena apologizes for her foolish heart, and decides to leave the wood. The two men tell Helena not to be afraid, that they will not allow Hermia to harm her.
Helena again insults Hermia, and Hermia again becomes enraged, incurring the insults of both Lysander and Demetrius. The two men decide to go out into the wood to find a suitable place for their fight. Helena says to Hermia she cannot win a fight against her, so runs away. Oberon, still watching asks Puck if he did this on purpose, Puck says he did not, then Oberon explains his plan for fixing the problem. Oberon tell puck to sound as if he were the other's rival, so to Lysander, sound like Demetrius yelling and to Demetrius, sound like Lysander, to draw them away from one another.
Oberon gives Puck a potion and tells him to put it on Lysander's eyes while he sleeps to correct his love, and in the morning it should all seem like a bad dream. Oberon says he is going to Titania and will ask for the Indian boy, then release her from the potion he used. Lysander wanders through the wood, following the voice of Demetrius who is actually Puck, until he eventually gets too tired to move on, and sleeps.
Puck uses the voice of Lysander against Demetrius until his is tired and frustrated, then falls asleep. Helena laments the events of the night in the wood, and sleeps, waiting for morning to make the way easier.
Hermia, tired and lonely, finds a place to sleep and wishes Lysander well if he fights Demetrius.
Puck comes and applies his remedy to Lysander.