It is problematic to write stories for a Role Playing Game. Usually, you write it for a bunch of people who are "in the know". Often, you need certain bits of information to understand it. You will not need much of information for this one, though. The next five sentences will tell you everything you have to know.

Delta Green (by Pagan Publishing) was created for the Role Playing Game Call of Cthulhu (by Chaosium). To get an idea of what it is imagine the X-Files set in the worlds of H.P. Lovecraft (but the first adventure was published one year before the X-Files hit the screen). The agents can have any agency background. DG is organized in cells. Code names are used within the cells. All of them begin with the same letter, e.g. Dirk, Detlev, Damon and Doris in D-cell. Sometimes the agents also use the last name Green.

If you want to get some more information take a look at Delta-Green.com. You will like it. For some information on H.P. Lovecraft click here. Basic informations on role playing games can be found here (in German). All these links are off-site.