Shakespeare makes Act V of Romeo and Juliet effective in the same way that modern storytellers do. He brings several aspects of the story line together at the end, giving the audience a sense of completion. It certainly isn’t a happy ending, but it is an ending that makes sense within the logic of the play.
First, we have an information problem that destroys the plan that Juliet and the Friar have concocted. When Romeo is not able to get a letter explaining the plan, he does not realize that the news of Juliet’s death is untrue. As he heads to the tomb, the Friar does also, as does Paris. There is also the possibility that Juliet might awaken in time for Romeo to find out that she is not dead.
All of these lines converge at that tomb in precisely the wrong way for the young lovers. Romeo, Juliet, and Paris end up dead. The only redeeming aspect of the resolution is the families’ promise to put aside their feud.