The page for this one shows just the text "There is nothing on this page."
Looking at the source, the body section looks like this:
<body> <h1>natas2</h1> <div id="content"> There is nothing on this page <img src="files/pixel.png"> </div> </body>
Hmm, I wonder what else is in the "files/" directory?
Browsing to http://natas2.natas.labs.overthewire.org/files/, shows there's also a "users.txt" file hosted there and clicking that you can find the password.