Now, Bethesda is preparing to ship what it considers its first true expansion to the game, The Elder Scrolls IV: The Shivering Isles, for both PC and Xbox 360 next month. The PC version of the pack will be sold only in boxed form at a suggested retail price point of $29.99, while the Xbox 360 version will be available exclusively as an Xbox Live Marketplace download at a price that is not yet finalized but likely to be roughly in line with that of its PC counterpart. As for the reasoning being the download-only model on Xbox 360, Bethesda's Pete Hines explained to Shacknews that there is simply currently no secure method available for releasing disc-based expansions on Xbox 360. Of course, The Shivering Isles will require a hard drive for Xbox 360 users (it's a little too big to make the 50MB memory unit limit) and can be acquired either with a free Xbox Live Silver or paid Xbox Live Gold subscription.

As for the PlayStation 3 version of The Elder Scrolls IV: Oblivion, which also ships next month, its version of The Shivering Isles will have to wait a bit. It was simply not possible to have prepared by the game's launch, but Hines indicated that Bethesda plans to have the PS3 expansion out some time this year.

I recently had the opportunity to get some hands on time with the PC version of The Shivering Isles, which proves to be a hefty addition to Oblivion. For those who wish to play the expansion without unnecessary amounts of plot knowledge, but who are interested to know the scope of its content, this preview will avoid a play-by-play recounting of the game's story, instead focusing more on overall breadth, the initial plot, and some noteworthy isolated incidents.

First, some numbers. According to Hines, the brand new world of The Elder Scrolls IV: The Shivering Isles is comparable to approximately one fourth that of Cyrodiil, but its content is packed much more densely, resulting in a richer experience. Overall, he expects players to clock out with over 30 hours of gameplay after completing its dungeons and quests. For Xbox 360 users, The Shivering Isles will also include ten new Achievements worth a total of 250 Gamerscore points. Just days ago, Microsoft announced that developers now have the option to add a limited number of new points' worth of Achievements to downloadable content. Hines said that Bethesda prodded Microsoft to make the policy change in order to facilitate a more complete experience for its expansion. "You think it was a coincidence that this policy came out this month?" he asked, laughing.

Upon installing The Shivering Isles on your platform of choice, you will simply enter the world of Oblivion as normal. Twenty four hours later, you will get wind of a rumor that a mysterious door has appeared on a small island in the middle of Niben Bay, which is marked on your compass. A bit of walking (or, better, teleporting) later, you'll discover the structure in question, a large grotesque three-headed statue with a glowing blue portal set into the middle head's gaping maw and a few NPCs hanging around outside. One of the NPCs refuses to speak with you, another appears to be insane, and the third informs you that, having entered and reemerged from the portal, the second NPC is insane. The informative one warns you not to pass through the portal yourself, but this is a video game. Eventually, you will be let through, finding yourself not in the Shivering Isles but in a small chamber containing an old man sitting at a table. After taking a set opposite him, he explains that the latest coming of a cyclical wave of destruction, the Greymarch, is threatening The Shivering Isles. Sheogorath, lord of the lands, is seeking a mortal champion to stave off the hopefully no longer inevitable, and this would-be hero may well be you.

Turn the page for more on the world of the Shivering Isles.

From that point, you enter another introductory area called The Fringe (by way of a stunning visual effect, the work of a man whose sole job on the project, Hines told me, was crafting nifty incidental visual effects) and soon encounter a monstrous troll-like creature called the Gatekeeper. He must be killed for you to enter the Isles proper, and creating a battle plan sufficient to take down the beast is the end result of a quest chain in a nearby town. Amusingly, you are later tasked with creating a new Gatekeeper to replace the one you killed, and in doing so you are able to play Dr. Frankenstein, mixing and matching from a selection of various body parts and weapons to create the abhorrent crime against nature of your dreams.

The world of the Shivering Isles, which exists as a completely separate environment from Oblivion's setting of Cyrodiil, is largely split into two thematically opposed regions: Mania and Dementia. The two zones are visually distinct, and are home to NPCs of quite different personality types. Mania is a bright, colorful land full of green grass and oversized tree-like mushrooms. Dementia, on the other hand, is a grey and somber swamp-like place, with gnarled trees and cold stone architecture. Between the two styles, Mania in particular is refreshing for being such a change from the more orthodox look of Oblivion's main game. It is not over the top, but its colors and vaguely insectoid flair give it an appropriately whimsical touch.

In addition to the scenery, Mania and Dementia also feature area-specific versions of certain creatures. Speaking of creatures, the expansion contains twelve new creature types, each with different varieties, including some that will be familiar to veteran Elder Scrolls players. Morrowind's Hungers return, as do the Golden Saints from the same game; here, the Golden Saints inhabit Mania, while their opposing variants the Dark Seducers inhabit Dementia.

Straddling the two zones is the capital city of New Sheoth, where Sheogorath resides. Adjacent to New Sheoth are the Maniacal city of Bliss and the Demented city of Crucible (note: area name adjectives may not be official Bethesda vocabulary). The former is ruled by the Duke of Mania and the latter by the Duchess of Dementia, for whom you will be completing a variety of quests on your way towards the larger objective of serving Sheogorath. Sheogorath himself is an amusing character who spouts rambling lines of dialogue in a Scottish-like accent not dissimilar to that of Sean Connery or Deckard Cain from Blizzard's Diablo.

With The Shivering Isles being an expansion and thus containing less overall content than the full Oblivion game, Bethesda set out to ensure that the content included in the pack is of sufficiently higher density. Thus, individual quests have more options and substance than those in the main game, and, notably, NPCs have largely been blessed with unique dialogue as well as more fleshed out personalities.

Though questing itself is handled essentially the same as it is in Oblivion, there are some new gameplay elements as well as some modified ones. For example, the prison system is handled in a different, and somewhat more brutal way. Upon being apprehended, your equipment is confiscated and you are placed in a dungeon--an actual, dungeon-crawling dungeon, not merely an underground cell. To reacquire your belongings, you must fight your way out of the dungeon with little more than your fists. Failing to do so, you may simply wait out your sentence.

Both main cities, Crucible and Bliss, have their own blacksmiths who can create unique equipment based on zone-specific materials. In Mania's Bliss the smith makes use of local amber, while in Dementia's Crucible items are forged with madness ore. Each smith has a price sheet with a list of weapons and the requisite amount of the material used, and in return for the appropriate goods the smith will craft for you the weapon or armor of your choice. One can also find weapon or armor matrices which, when given to a smith along with enough amber or madness ore, will return a special enchanted weapon. Of course, there is also a whole new set of premade items to be found throughout the world of the Shivering Isles itself.

All in all, it likely that the imminent release of The Shivering Isles will keep Oblivion hanging around on the list of most played Xbox Live games for some time to come. Look for it when it ships to retail PC and is available through Xbox Live Marketplace for Xbox 360 next month. Also, check back with Shack tomorrow for an extensive interview with Bethesda's Pete Hines on all aspects of the company's current and future endeavors.