Based on the ARG and info revealed so far, here's what I think is planned for us in terms of the story and game play: I predict we are going to get to play (battle) on each of the planets mentioned from Tuesday (Mars) through to Saturday (Saturn). These will have been planets that we explored and probably terraformed with the coming of the Traveller and beginning of humanity's Golden Age. With information from the pre-order leaflets, I think that each of the planets are now inhabited by alien species that are the enemies from the darkness of the galaxy, who've been drawn by the presence of mankind. And these enemies are now focusing on Earth and the Last City as a means to destroy us as a species ("And maybe it never was." :poem 1 - humanity's voice) Monday's poem is related to the moon as we know it through the naming of the geomantic symbol, but I believe it relates to the Traveller (a moon-sized, moon-like body) itself and the message/lesson it intends for mankind and its now role as our protector. My theory is humanity used the Traveller in the wrong capacity when it first arrived, we explored too much, too fast, proclaimed ourselves to be great beyond reckoning and generally did something bad enough to get under the skin of a previously unknown enemy. We allowed our voice to be heard when we shouldn't have and now we're in trouble. So the enemy has claimed what once was ours, the planets in the Solar System that we'd inhabited and also possibly other areas on Earth - as other info on the leaked leaflets mentioned it being the last safe city, implying others exist that are no longer safe for humankind. The presence of the Traveller over Puerto Princessa enables the Last City to be defended where otherwise we've lost everything else we had or gained. It will also provide the means through which we can still access/travel to our former colonies. In terms of the factions associated with the game, mankind has devolved into rival factions following the fall from the Golden Age, each blaming the other and/or wanting to control the defence of the Last City and how humanity carries the fight to the enemy. The naming of the possible alien species as the "Fallen" may intend that they were once human, captured on the planetary colonies but now influenced/modified and controlled by the enemy who themselves will be represented in the game as other enemy types. Whether I am right about the Fallen or not, all this ties together in providing a number of different theatres of war, earth itself and the planets we'd inhabited, as well as various enemy types. The Traveller's technology provided humanity with the ability to travel/jump to the other planets in the Solar System, an ability we still can use that allows missions and campaigns to repel the enemies on those planets surfaces. Co-op gameplay comes about through joint faction missions to take back the former colonies or to retrieve past human information or enemy intel from enemy territory on those planets, or providing mass attack repulsion missions from the walls and surrounding lands of the Last City. Competitive multiplayer is possible whilst still in character with the different factions competing for footholds in the former colonies in the Solar System, which would further their ambitions to control, sway the governance of the Last City and humnakind as a whole. Socially, Bungie can ties this all into online. live operartions maps of Earth and the former colonies, showing enemy control/incursions and player gains & losses from a humanity stand-point and on Faction-specific levels. They will also, similar to how Mass Effect 3's multi-player, issue missions and operations from the social hub on the web that will exist and occur whether a particular player is involved or not, providing a dynamic narrative to the game universe outside of whatever specific single player game play they will offer. How the 7th day's symbol and the Sun comes into it, I'm not entirely convinced yet, and whether there is a specific set of "Guardians" (much like the Spartans) or whether we can all exist as Guardians at the same time in a fully connected gameworld I'm not sure about (possibly millions of Guardians then) - I'd side on the idea of a subset or defined number of Guardians being possible to ensure the player retains the ability to be and appear "special" in all of this. Anyways, that's all a bit long-winded but that's my theory just prior to the reveal. If some of that is proved true I'd be quite happy indeed!