Microsoft's press conference at E3 gave us our first glimpse at "Halo: Reach," but it wasn't exactly robust. The teaser ominously stated, "From the beginning, you knew the end," and featured a lot of combat chatter, but if you're not in the know with the expanded Halo universe you were probably left scratching your head. We're here to help.
"Halo: Reach" revolves around the events detailed in the 2001 novel, "Halo: The Fall of Reach." It's a prequel to the main "Halo" storyline (again, alluded to in the trailer). The book's protagonist was a younger Master Chief, who, along with a squad of SPARTAN soldiers, tried to defend the planet from the first Covenant invasion. Unfortunately, as the novel's title hints, things didn't go so well. If you'd like to know more about the game's probably story, definitely check out the book (as well as the subsequent sequel, "Halo: First Strike."
As for the game, your guess is as good as mine. The developers are decidedly mum, saying only what Brian Jarrard gives us in the video below. We do know that there will be a multiplayer beta, and that people who buy "Halo 3: ODST" will get a download code to access that beta. There's also a release date planned in late 2010.
So yeah, sorry to disappoint. Microsoft and Bungie are on total lock-down with regards to anything "Halo: Reach," but once "ODST" comes out we should definitely know a bit more.