Look at the parts of a plot line in a basic short story:
- Exposition: background information, setting, character introduction, conflict.
- Rising Action (and complications): events leading to the climax of the story.
- Climax: the highest point of action in a story.
- Resolution: the solution to the initial problem.
Each of the acts in "Romeo and Juliet" can be fit into one of these parts.
The prologue in Act 1 presents most of the exposition of the story. It is brief but complete. The characters (though not by name) are introduced, the problem/conflict of the two families is introduced, and actually, the end of the story is revealed. The initial fight scene actually demonstrates the conflict between the two houses. Finally, the Prince's decree at the end of this scene is what initiates many future complications in the story.
Acts two through four and the very beginning of Act 5 are all parts of the rising action of the play. These acts, of course, contain the "meat" of the story which continues to build in action, emotion, and anticipation of the climax. Several complications are introduced as the action progresses, including Juliet and Romeo falling in love and marrying without consent, the deaths of Mercutio and Tybalt, and the banishment of Romeo.
The play ends almost as abruptly as it began, therefore, the climax and resolution take place in Act 5. The deaths of Romeo and then Juliet are the very peak of the action in the story. As a result of their deaths, however, the two families realize the errors of their ways and finally forgive one another, which is the resolution to the original conflict.