LotR: The Battle for Middle Earth (Hard Good Campaign) 5: Osgiliath and Spiders

The ancient evil stirs in the east. As Sauron's power grows, hope for the free peoples of Middle Earth dwindles. Luckily, the One Ring, the source or the Dark Lord's power has been found. If the free peoples can throw it into the molten magma of Mount Doom, then Sauron will be defeated. This quest must be done in secret for if the forces of evil find out, their victory will be assured.