The Agency is a sourcebook for use in investigation campaigns that feature a paranormal or science fiction twist. This book details the Periphery Detective Agency, a private investigation firm that specializes in cases that have a supernatural, otherworldly, or just plain bizarre twist. You can create an entire campaign based on the agency where the player characters are rookie detectives in the employ of Periphery. Alternately, you can feature agency personnel as NPCs that occasional enter into the campaign to work with (or against) the characters.
You can use this sourcebook for a number of different genres, from near future science fiction to urban fantasy and more. Any adventure setting that combines investigation with supernatural or science fiction elements can be a home for the Periphery Detective Agency.