Monument of the Ancients (2011)

From the front of the book:
Panicked refugees are pouring into the port city of Phlan, fleeing from barbarian attacks in the Moonsea North. Something ominous and ancient drives the horse nomads to attack their neighbors. Poised to shatter the ancient monument keeping him from Faerûn, a “lost god” from Toril’s past sends an agent from the Elemental Chaos to herald his long prophesized return... A Living Forgotten Realms adapted adventure set in Phlan for characters levels 11-14.
To use this adaptation document, you will need a legal copy of the full adventure, which is found in Issue #170 of Dungeon Magazine, part of D&D Insider on the Wizards of the Coast website. This adventure is longer than a standard Living Forgotten Realms adventure; we recommend that you allow a minimum of 8 hours of play time. The adaptation gives rewards roughly equivalent to a two-round LFR adventure. If time is tight, there are a number of optional encounters that you can omit.