A Chorus opens the play with a fourteen-line sketch of everything to come. Two families of equal rank in Verona, the Montagues and the Capulets, are locked in an old feud that keeps spilling civil blood into the streets. From these 'two foes' a 'pair of star-cross'd lovers' will be born, and the Chorus states plainly that only their deaths will finally bury their parents' strife. The first scene then dramatizes the feud directly: servants trade insults, a brawl erupts, and the Prince of Verona arrives to declare that the next man to disturb the peace will pay with his life.
Romeo, a Montague, is at first lovesick over a woman named Rosaline who does not return his interest. Persuaded to crash a Capulet feast in disguise, he sees Juliet and forgets Rosaline instantly; she is equally struck, and only afterward do they each learn the other belongs to the enemy house. That night Romeo lingers beneath Juliet's window and overhears her wishing he were not a Montague: 'O Romeo, Romeo, wherefore art thou Romeo?' They exchange vows on the spot and agree to marry the very next day. Friar Lawrence consents to perform the wedding, privately hoping the match will turn the families' rancour into love.
The secret marriage holds for only hours before the feud destroys it. Tybalt, Juliet's hot-tempered cousin, picks a fight; Romeo, now secretly Tybalt's kinsman by marriage, refuses to duel, so his friend Mercutio fights instead and is killed under Romeo's arm, cursing 'a plague o' both your houses' as he dies. Enraged, Romeo kills Tybalt and cries that he is 'fortune's fool.' The Prince banishes him from Verona on pain of death. In a single afternoon the lovers' future collapses: Romeo must flee to Mantua, and Juliet, who has just become a wife, learns that her husband has killed her cousin.
With Romeo gone, Juliet's father suddenly insists she marry Count Paris within days, not knowing she is already wed. Cornered, she turns to Friar Lawrence, who devises a risky plan: she will drink a potion that mimics death, be laid in the family tomb, and wake forty-two hours later when Romeo, warned by letter, will be there to carry her away. Juliet takes the drink alone and terrified. The household, believing her dead, turns its wedding preparations into a funeral. The plan depends entirely on a letter reaching Romeo in time, and that letter never arrives.
The final scene unfolds in the Capulet tomb. Romeo, told only that Juliet is dead, buys poison from an apothecary and comes to die beside her. Believing her a corpse, he drinks the poison: 'Thus with a kiss I die.' Minutes later Juliet wakes to find him dead, and with his dagger kills herself, calling it 'happy.' The Friar arrives too late, the families gather over the bodies, and the truth comes out. Montague and Capulet at last make peace, vowing monuments to each other's child. The Prince closes the play by naming the price of the reconciliation: 'For never was a story of more woe / Than this of Juliet and her Romeo.'