This video, like the Horde one posted earlier, relates to quest chains for the new factions appearing in Krasarang Wilds with Patch 5.1. The Horde faction is the Dominance Offensive, but our interest here lies with the Alliance Faction, Operation: Shieldwall. The faction is stationed in Lion's Landing, where they landed after sending their elite force ahead to assist the White Pawn.
Like almost all Pandaria-based factions, Operation Shieldwall comes with quest chains, from which this spoiler-tastic video is extracted. These quests award reputation, which can also be earned via the completion of daily quests, and allows the purchase of various items.
But that's not the sole focus of this video! More spoilers after the break.