Tybalt wanted to fight Romeo because he showed up to the Capulets party but Romeo didn't want to because Tybalt is Juliet cousin. So Mecrcutio fights Tybalt instead and Tybalt ends up killing him so Romeo kills Tybalt. Romeo gets exiled from verona.
The Nurse is telling Juliet how Romeo killed Tybalt and how Romeo got kicked out of verona. But Juliet happy Romeo wasn't the one that got killed.
Romeo goes to Friar to tell Romeo what happen and Friar helps him and lets him stay while the news goes down.