Plugins tab won't open at all

I’m encountering an issue I haven’t seen before in WP.

When I click the Plugins tab in WP admin I get a 404 “Not found” message. The plugins URL is http://www.carrierickey.com/wp-admin/plugins.php but it just won’t open. Everything else in WP admin works, e.g. http://www.carrierickey.com/wp-admin/edit.php

Any ideas on what the issue could be? I’m hesitant to mess with the plugins dir on the server, since I won’t be able to manage the plugins in the admin screen.