These campaigns use the GURPS system with Tri-Tac's Bureau 13 campaign setting and background (somewhat modified by the GM). The basic concept is that the PCs are all members of a top secret government agency that investigates (and often suppresses information concerning) the supernatural-- sort of like the TV show X-Files. The difference is that the Bureau 13 agents are often supernatural themselves. Those that aren't, have usually had major encounters with the supernatural.
My first character was Halcyone Kent in Jack Shot's campaign. The team was stationed in New York city and covered most of the East Coast.
My first character in Chris Canary's campaign was Cynarra Lambard. The team is stationed in Los Angeles and covers most of the West Coast.
Cynarra eventually died and was replaced by Nadezhda "Nadya" Grigorova