Romeo loves Juliet and Juliet loves him. She is having some doubts because sometimes when Romeo is not there Mercutio talks to her and comforts her lounging for love.
Mercutio tells Juliet that she loves him thinking that Romeo wasn't there but he was listening to him the whole time. When Juliet was about to tell him that she loved him too but then Romeo comes and stabs Mercutio in the heart killing him.
Juliet takes her life because she can't live knowing that now her love is dead because of her. This leads to Romeo realizing that now he has no one and so he takes his life as well falling over the graves of Mercutio and Juliet, which were right next to each other.
In the end, the people of fair Verona gets together after losing so many people to love. They decide it is better to live their life while they have it.