If a defendant fails to answer, the plaintiff can apply for an order of default, and then get a default judgment against the defendant for the amount requested in the complaint. And then the defendant has a big old judgment against them and they didn't even fight it.
First, a default will be entered which precludes the defendant from responding to the complaint.
Second, a default judgment will be entered based on the amount of damages proved up by plaintiff.
As a practical matter, the defendant will have six months to set aside the judgment, assuming it was properly served, and forever if it wasn't.
So be sure and properly document the service of process.