It is next to last in the series of quests given inside the tower located in The Village of Shin from the Fallen Dynasty Adventure pack and is called "The Rift." Completing it gives you access to the top level of the tower.
Lu Sywaka has tasked me with finding out more information about the place beyond the portal. Surely there will be more information somewhere within the port itself.
Search for the "Clues" that Master Lu Sywaka has sent you to find:
65.85, -69.92, 25.46 - on top of the red dresser
-46.31, -33.18, -26.09 - on top of a bookshelf with other non-clickable books
59.08, -22.71, 6.94 - on top of a red chest
0.82, -24.04, 84.74 - on top of a small red dresser
Upon finding the fourth book and reading it, you will be granted a Lu Sywaka's Meditation Focus Stone. Using this will call Master Lu Sywaka to you to continue with the quest.
Head to 0.29, 1.73, 5.99 and kill Mistress Zhvari, Nizari'zhi. She hits very hard. To get to her, find your way to the top level and kill both K'hazid38, 15.3, -23.3 and K'huthas-36.3, 15.3, -21.7 . Doing so will cause the forcefield wall behind the other named to disappear, allowing you to jump down to the named.