What happens if the defendant fails to show?
If the defendant(s) in your case have been served properly and the "proof of service" or "affidavit" has been filed with the courts; the defendant(s) in your case must make the appearance on that specified trial date. If they fail to appear, the judge will award you with a default judgment (you win the case).
In most state (Texas/Georgia/Arizona/VIrginia/Connecticut - we will provide you instructions), the defendant has to reply back to the courts once they have been served. If the defendant fails to make the response, you will win the case by default.