Act III Scene I: The scene started with Benvolio and Mercutio just talking then Tybalt came and killed Mercutio. Romeo was unsuccessful of being the peacemaker this scene, so to avenge Mercutio's death, Romeo killed Tybalt. We learned in this scene that Mercutio was actually part of the Capulet family at one point. And what's worse about this scene, after the death of Mercutio and Tybalt, Prince Esculaus banished Romeo out of Verona. So that means that he can't see Juliet anymore without getting killed.
Act III Scene II: Juliet just got the news of Tybalt is dead and Romeo is banished. She was more saddened by the fact that Romeo was exiled because she said she would rather Tybalt die 10000 times than Romeo be exiled. But other than that Juliet stays loyal to Romeo. And she told the Nurse to go see Romeo and tells her that she will stay loyal to him no matter what.
Act III Scene III: He is weeping all of his tears about the situation that he is in at Friar Lawrence's Cell. When the Nurse came in to tell Romeo that she will stay loyal to him, the Friar and Romeo talked alone. Where the Friar told Romeo that they should be thankful for everything, he should be dead right now, he just killed his wife's cousin and she is not going to kill him. So you should be thankful for everything then Nurse told Romeo to go to Juliet.
Act III Scene IV: This scene was about what should Juliet's future should be. Lady Capulet says that Juliet is sad because of the loss of Tybalt, which is not true, and Lord Capulet is talking about her marrying Paris, one of the finest gentlemen' in Verona. And they are going to make them marry at Thursday
Act III Scene V: Right before this happened. Romeo and Juliet were saying their goodbyes and then Lady Capulet told Juliet the news of her marrying Paris. Juliet didn't want to, so then she said to Juliet tell your father that. Juliet told her father that he wasn't really thrilled about that fact. So we go now, Lord Capulet shows his anger and tells Juliet that you are marrying Juliet or your not his daughter anymore. Then after this, Juliet asks the Nurse what to do, but she is unloyal and says to marry Paris, so now Juliet doesn't trust the Nurse anymore.