1. Tybalt, a Capulet, encounters Romeo and his friends, who are disguised as musicians, in the streets.
2. Tybalt recognizes Romeo and is enraged by his presence, especially since Romeo attended the Capulet ball uninvited.
3. Tybalt draws his sword and challenges Romeo to a fight, seeking to avenge the perceived insult to his family's honor.
4. Romeo, filled with love for Juliet and unwilling to engage in violence, tries to avoid the confrontation.
5. Mercutio, Romeo's close friend, intervenes and draws his sword to defend him.
6. During the sword fight between Mercutio and Tybalt, Romeo attempts to separate them but unintentionally gets in the way.
7. Tybalt takes advantage of the situation and fatally wounds Mercutio, who dies in Romeo's arms.
8. Romeo is grief-stricken and guilt-ridden over Mercutio's death, which triggers a powerful desire for vengeance.
9. Romeo charges at Tybalt and kills him in a fit of anger, avenging Mercutio's death.
10. The Prince of Verona arrives at the scene and is furious at the bloodshed caused by the two families' feud.
11. The Prince banishes Romeo from Verona, declaring that if he ever returns, he will face the penalty of death.
Act 3, Scene 4 of Romeo and Juliet is significant as it escalates the feud between the Montagues and Capulets to a new level of violence. It sets in motion a chain of events that ultimately lead to Romeo and Juliet's tragic love story.