UPDATE: According to Xbox Live the mystery is a new campaign experience. The trailer download page on Live includes the text, "High action and deep mystery await players in this new Halo 3 campaign experience. Prepare to Drop!" This is getting interesting!

After an unfortunate false-start at E3 2008, Bungie has finally revealed its hidden agenda for world domination. Today at 7:07am PDT, Bungie teased what appears to be a story expansion to Halo 3. Details are scarce but the trailer begins with falling escape pods onto a city landscape that seems ripped right out of Halo 2's infamous E3 in-game demo.

The trailer showcases a giant explosion that levels the clean city into a burning pile of rubble ending with the tag lines, Halo 3. Prepare to Drop.

If you ask us, this screams ODSTs! Not that we're swayed by the itchy typing fingers of hardcore fanboys and girls but we're all excited for whatever this title or expansion could mean for the Halo universe! Expect every morsel of information here on X3F as soon as it becomes available.

This article was originally published on Joystiq.