The official Darker than Black: Ryuusei no Gemini website has posted a preview of this week's Darker than Black: Ryuusei no Gemini episode 5, which is titled (roughly translated) "The Gunsmoke Flows, and Lives Flow With It".
Misaki Kirihara has come into contact with a mysterious pair of twins, and learned of the "Mitaka Document" and "Izanami". The very same Izanami contacts her with orders. Meanwhile, Suou's current hideout has been discovered by a Contractor named Michiru, who is connected to Norio's past. Shion gets his first request as a Contractor to destroy a shipment in the harbor.
The episode will air on November 6, 2009.