Because you have killed out of revenge I will banish you instead of sentence your death.
Romeo and Juliet first saw each other and fell in love at first sight. The party is at the Capulet house and Romeo snuck into the party to see his love Rosaline but ended up falling in love with Juliet. The they learned that they are part of different families that hate each other.
Banishment
Romeo and Juliet run to Friar Lawrence so they can get married. They think that maybe he will help them. Friar Lawrence agrees to marry them because he thinks that maybe it will stop the feud between their families.
The Plan
Tybalt and Mercutio get into a fight because Tybalt wants to fight Romeo but Romeo does not want to fight Tybalt. Then Mercutio steps in and ends up getting killed. This makes Romeo mad so Romeo decides he will fight Tybalt as well.
The "Funeral"
Your beauty is still there even when you lie dead.
When Tybalt killed Mercutio it made Romeo really mad. Out of anger and revenge Romeo killed Tybalt. That lead Prince Escalus to banish Romeo.
Juliet takes the vial that Friar Lawrence gave her for the plan. It makes her look like she is dead but actually it's a potion where she'll wake up in 48 hours. She takes this so she can be with Romeo.
Romeo heard that Juliet was dead and he wanted to come see her. He didn't get the letter in time saying that it was just part of the plan. He didn't want to live with out her so he decided to kill himself. Then Juliet woke up and saw Romeo dead and killed herself too.