The Laundry Files Roleplaying Game is based on the best-selling novels by Charles Stross. In the game, you play officers of the Laundry, that eccentric and underfunded agency dedicated to protecting the United Kingdom from unthinkable horrors. The Laundry uses the Basic Roleplaying System - the same system that powers the classic Call of Cthulhu roleplaying game (so you can easily convert adventures from one game to the other).
As Laundry staff, you're trained to deal with the weird and ghastly spawn of the Mythos, you're equipped with the best equipment your committee-approved mission budget can buy, and you've got back-up on call from the SAS. All of that means you're only terrifyingly underprepared, as opposed to completely screwed, when the shoggoth hits the fan.