Esoterrorists
Esoterrorists is a GUMSHOE setting where the players are investigators working for a secret society opposed to evil occult conspiracies and general nastiness.
Gumshoe is a RPG focused on investigations, specifically negating the chokepoints related to players missing certain vital clues.
It's a pretty simple system, and Esoterrorists is a pretty cool setting.
I'd be looking for 4-6 characters recently recruited to the secret society. Some might be from law enforcement or intelligence agency backgrounds, others might be journalists, academics, or even criminals - anyone with the skills to investigate these things, really.
Give a shout out if you're interested. Foreknowledge of the setting or system is unnecessary. We'll probably start with some canned investigative scenarios to get used to the system first.