For a comprehensive summary of events, follow the link below to eNotes. But here is a brief blow-by-blow:
Day One: An old feud between two elite families, the Capulets (Juliet) and Montagues (Romeo) erupts in the streets of Verona. Despite their rivalry, Romeo is convinced to go to a masked ball given by the Capulets. There, under the cover of disguise, he beholds the fair Juliet. Romeo later (beginning of Act II) overhears Juliet at her window confessing her love for him. He reveals his presence to her and in a passionate love scene, the two vow to wed.
Day Two (Act II): In the morning, Juliet send her nurse to make arrangements for her wedding with Friar Lawrence. She hopes that perhaps the wedding will ease the age-old feud between the families.
Day Three: Romeo returns from his wedding and he, along with his friends Benvolio and Mercutio, run into Tybalt, Juliet's cousin. Tybalt taunts Romeo. Mercutio takes the quarrel upon himself. Mercutio is slain by Tybalt. Romeo in turn slays Tybalt. Romeo is banished from Verona by the Prince. Juliet learns of the news about her cousin and her husband and is distressed. Juliet's parents, knowing nothing of her marriage, insist that marrying Paris (a kinsman of the Price) will ease her grief.
Day Four: Juliet consults the Friar who comes up with the plan to have her "appear" to be dead, so that she will be left alone in the Capulet burial vault and Romeo can come take her away. Juliet follows the Friars instructions.
Day Five: Because a letter from the Friar explaining the deception of Juliet's death is late, Romeo thinks Juliet is truly dead. He procures an actual poison. As he is opening the Capulet tomb, Paris discovers Romeo who is obliged to kill him. Romeo sees the "dead" Juliet, takes the potion and dies. The Friar has just then come in to release Juliet from her pseudo-death, but Juliet sees her beloved dead. She quickly realizes Romeo's error. In despair, she takes her own life with a dagger.
The feuding families, witnessing the deaths of their children, finally resolve to put their pasts behind them and reconcile.