For the second month in a row, ArenaNet will release a monthly event for Guild Wars 2. Following the conclusion of the Guild Wars 2 Halloween–themed "The Shadow of the Mad King" event in October, the new mysterious event, titled "The Lost Shores", will begin sometime in November 2012.
Not much is known about "The Lost Shores" except that "something stirs in the Sea of Sorrows", the body of water in the middle of Tyria.
Some teaser text reads: "Unravel a mystery of monstrous proportions in The Lost Shores, a massive one-time world event that will change Tyria forever!"
There were some screenshots released, but they don't really reveal anything.