In a special pre-launch group interview, World of Warcraft Game Producer George Velev revealed a few more details about the upcoming Story Mode for Nerub'ar Palace, which will allow players to experience the culmination of the initial War Within campaign by facing off against a significantly reduced difficulty version of Queen Ansurek!
Specifically, the story mode difficulty will be very low, and although the boss will not drop any loot, there will be an associated quest which will reward players for completing it.
The goal of story mode is to allow players who just want to see the story and have a chance to participate with the encounter, so the difficulty will be very low. In terms of how you sort of get into story mode, players would be driven towards it by a quest, and while there will be no rewards for defeating the boss, there will be rewards for completing the quest.
Revealed this past May, Story Mode allows players to experience the culmination of the initial War Within campaign by facing off against a significantly reduced difficulty version of Queen Ansurek in groups of 1-10 players. Although initially set to release Story mode alongside the final wing of LFR, the date was moved up to release alongside Mythic raids on September 17th.