This is a double length RPGA Living Forgotten Realms adventure designed for play over 8 rather than the regular 4 hours. The Core Special releases are designed to be slightly more challenging that regular RPGA adventures.
This adventures was available with a staggered release, initially only playable at specific gaming conventions before general release to RPGA players:
August 14, 2008 - Gen Con Indy
August 28, 2008 - Gen Con UK
August 29, 2008 - PAZ (Penny Arcade Expo)
September-October 2008 - other select conventions
January 1, 2009 - general release
From the front cover of the adventure:
Zhentil Keep is a city with a storied history, even if most of the tale is not fit for innocent ears. A mission to find the wayward son of a wealthy merchant leads deep into the secrets, deceptions, and brutal power on which the dreaded Zhentarim built their ominous keep. A Living Forgotten Realms two-round special adventure set in the north section of Zhentil Keep for characters levels 1-4.
This adventure retires from RPGA-sanctioned play on December 31, 2011.