I would hope that the storyline of Halo 3 Recon will take us past the end of Halo 3, where MC is nearing that mysterious planet (with the ominous music), which seemed an obvious setup for a sequel. Bungie has sworn that Halo would be a trilogy, and they're tiptoeing around that by making another Halo 3 game, not 'Halo 4', so if they take the story far enough, we'll know what happens on that planet without them having to make yet another game.