Mail - Phantom "New Message" alerts that never go away

Comrades,

I'm on a Mac Pro running Mac OS 10.8.4, all apps up to date, etc.

Using Mail as the client for my exchange email account at work, I have encountered a strange issue whose solution eludes me... There is a numeric alert on my inbox that indicates I have three unread messages, when no such unread messages exist. I have attempted the following remedies to no avail:

Viewed All Unread Messages

Marked All Messages "Read"

Restarted Mail

Restarted Computer

Restarted Computer with PRAM Reset

Removed/Added Email Account (twice)

Drank a lot of whiskey

Registered for Apple Support Communities

Any and all advice would be appreciated.