In Act IV, Juliet states that she would rather die than be forced to marry Paris, so her and Friar Lawrence come up with a plan to fake her own death to avoid Paris and Juliet's wedding. The plan is also carried out in this scene and her family as well as Paris mourn her "death".
In this scene Juliet expresses her discontent about having to marry Paris and states that she would rather die than have to marry him. Juliet and Friar Lawrence than come up with a plan for her to fake her own death by drinking a sleeping potion.
In this scene Juliet goes to her father and convicts him to move up the wedding so that she can go through with her plan to fake her death.
In this scene Juliet is having doubts about the plan and is worried that the potion will actually kill her. But she ultimately goes through with the plan and drinks the potion.
In this scene the Nurse is sent to wake Juliet for the wedding, but finds her "dead" in her chambers.
In this scene the capulets and Paris all mourn the "loss" of Juliet.