The Past is Doomed (2012)

From the credits:
This scenario was written by Geoff Gillan and first published in the Chaosium Digest, Volume 9, Numbers 9—11 (February, 1995).

From the PDF:
The Past is Doomed is a detailed scenario set in the Arkham of the 1990s. It attempts to put the Arkham of that decade in perspective, measured against its history throughout the 20th Century. Unlike many Call of Cthulhu scenarios, the setting of this adventure is integral to the plot -- relocating it to another place or time is certainly possible (see sidebar), but requires some effort on the part of the Keeper.

This scenario’s use of a phantom, yet sometimes intrusive past employs some of the mechanics of the Dreamlands, explained briefly in Call of Cthulhu Sixth Edition (and more fully in H.P. Lovecraft’s Dreamlands). These mechanics are fully explained within the scenario, and Keepers and players should not consider this piece a Dreamlands one, merely one with dream-like sequences.

The Past is Doomed also reflects on the past of the American nation and what has brought the country to the unique place it occupies at the end of the 20th Century. It also explores some of what the forces and beings of the Cthulhu Mythos have been doing in that era. This forms a kind of link between activities of 1920s Call of Cthulhu investigators and those active in more modern times.

This scenario is available as a free download (see links section at bottom of page.)