Nova Prospekt 

A prison fort located on top of a large cliff, after a treacherous battle on the coast from escaping the Combine from Highway 17. It is known to be a deadly place, where people are usually and at a guess, bad. The area is unknown to many; the Xen aliens that ally with the humans, the Vortigaunt, sent pictures back to Eli, but they are all bad. It is in here that people are placed in pods and literally worked on by scientists, and turned into human like slaves for the Combine, also known as "Stalkers". In Nova Prospekt, your objective is to rescue Eli with Alyx and escape with him safely. The ending of Nova Prospekt ends with Eli and Mossman, but unfortunately, they're warped to different coordinates, and not to Dr. Kleiner's lab. When the portal resets, Gordon and Alyx take the warp. After the warp is destroyed by the Combine, the teleport warps the two slowly to Kleiner's lab, but it takes over a week to execute the warp to Kleiner's lab.

Barney: He was about to board the express to Nova Prospekt!
Man at N.L.O: One man alone probably can't get into Nova Prospekt, but one man with a pack of antlions... well, that's a different story.

Nova Prospekt by Voltage December 17, 2005