plugin to make arrow appear letting people know more content is available

HI,
I building a site for a client here:
http://www.oliveryarbrough.com/

He wants an arrow to appear letting people know that they can scroll down to see the rest of the content on the home page. Is there a plugin that will place an arrow pointing down letting people know this? I know it's a unique request but he said he wants to "idiot proof" the site.