The expansion to Titan Quest takes the hero down to the plane of Hades, the mythical greek world of the dead. More sinister and dark than the original, Immortal Throne starts the player on his journey via the River Styx. In greek mythology the river was the passageway to Hades in order for the souls of men to be judged. Those worthy will be sent to Elysium while the unfortunate ones are banished to Tartarus. The Player will also meet souls of men who were not judged but merely wander the endless plane of Hades.

The river Styx divides the level into two main regions. A drier, rocky highland which I already described, and a rising flood plain which breaks this region into a series of small islands set amongst a shallow watery swamp area. These islands help form a dual elevation gameplay space where players will fight through the swamp below and over a series of islands connected with bridges. The islands themselves hold the small military camps set up Hades advancing army. These are mostly small supply depots used by front line scouts from the daemon army, some of whom have already moved out of Hades to wage their war on Greece. via IGN

In this epic quest of good versus evil, players will encounter the greatest villains of Greek mythology, brave the attacks of Cerberus, and hazard the banks of the River Styx. Along with new foes, players will fight alongside Agamemnon and Achilles, interpret the prophecies of the blind seer Tiresias, and use the wiles of Odysseus to conquer this dark new adventure.

* 10 Additional Character Levels: Bring existing and new characters to new heights with higher level equipment and skills.
* 8 New Character Classes: Immortal Throne features an entirely new skill mastery, which combines with existing skill masteries to create eight new exciting character classes.
* New Exotic Monsters and Locations: Quest through exotic locations in the Mediterranean area and ultimately descend across the river Styx into the heart of Hades. Defeat terrifying new monsters on your way to victory!
* Artifacts & Enchanters: A new type of rare equipment that gives the player a powerful bonus. Plus, new non-player characters that can create artifacts from recipes.
* More Unique Equipment: Uncover hundreds of powerful new unique items and use Caravans to store them as you quest through the Underworld of Hades.

via THQ